S-100 Immunostaining Research Articles

Long-Term Denervated Rat Schwann Cells Retain Their Capacity to Proliferate and to Myelinate Axons in vitro.

Functional recovery is poor after peripheral nerve injury and delayed surgical repair or when nerves must regenerate over long distances to reinnervate distant targets. A reduced capacity of Schwann cells (SCs) in chronically denervated distal nerve stumps to support and interact with regenerating axons may account for the poor outcome. In an in vitro system, we examined the capacity of adult, long-term denervated rat SCs to proliferate and to myelinate neurites in co-cultures with fetal dorsal root ganglion (DRG) neurons. Non-neuronal cells were counted immediately after their isolation from the distal sciatic nerve stumps that were subjected to acute denervation of 7 days or chronic denervation of either 7 weeks or 17 months. Thereafter, equal numbers of the non-neural cells were co-cultured with purified dissociated DRG neurons for 5 days. The co-cultures were then treated with 3H-Thymidine for 24 h to quantitate SC proliferation with S100 immunostaining and autoradiography. After a 24-day period of co-culture, Sudan Black staining was used to visualize and count myelin segments that were elaborated around DRG neurites by the SCs. Isolated non-neural cells from 7-week chronically denervated nerve stumps increased 2.5-fold in number compared to ~2 million in 7 day acutely denervated stumps. There were only <0.2 million cells in the 17-week chronically denervated stumps. Nonetheless, these chronically denervated SCs maintained their proliferative capacity although the capacity was reduced to 30% in the 17-month chronically denervated distal nerve stumps. Moreover, the chronically denervated SCs retained their capacity to myelinate DRG neurites: there was extensive myelination of the neurites by the acutely and chronically denervated SCs after 24 days co-culture. There were no significant differences in the extent of myelination. We conclude that the low numbers of surviving SCs in chronically denervated distal nerve stumps retain their ability to respond to axonal signals to divide and to elaborate myelin. However, their low numbers consequent to their poor survival and their reduced capacity to proliferate account, at least in part, for the poor functional recovery after delayed surgical repair of injured nerve and/or the repair of injured nerves far from their target organs.

Can we differentiate malignant peripheral nerve sheath tumor from benign neurofibroma without invasive sampling

One of the most important benign tumors in neurofibromatosis type 1 (NF1) is plexiform neurofibroma, and there is a risk of developing malignant peripheral nerve sheath tumor (MPNST) throughout life approximately 10%. However lesion characterization by anatomical imaging methods are not possible. Because of that most of cases goes to biopsy. Using of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) for lesion characterization can be helpful in NF1 patients. We aimed to present an example of the efficacy of FDG-PET/CT in distinguishing benign neurofibroma from MPNST. A 6-year-old male patient who had NF1 admitted to emergency service due to high fever. Acute upper respiratory tract infection was diagnosed; antipyretic and abundant fluid intake was suggested. When high fever continued, the patient referred to our hospital on detection of axillary lymphadenopathy. Leukocytosis was detected in patient's blood count. Sedimentation was 54 mm/h, C-reactive protein 166 g/L, and lactate dehydrogenase 276U/L. Blood and throat cultures did not show pathogenic bacteria. In serological tests, VZV-IgG, EBV-VCA-IgG, and CMV-IgG were avidite positive; Hepatitis B Ag, Anti-HIV, Anti-HAV IgG and IgM, Anti-HCV, EBV-VCA IgM, and VZV-IgM were negative. Based on these results, cervical and thoracic contrast-enhanced computed tomography was performed on preliminary diagnosis of MPNST. Solid lesions with rounded margins, large one being 49 mm in size, that extend from superior mediastinum to posterior mediastinum, left axillary region, and left part of neck were detected, and they were surrounding the vascular structures. Since neurofibroma, MPNST, and lymphoma could not be distinguished, patient referred to FDG-PET/CT scanning. In FDG-PET/CT, highest lesion maximum standardized uptake value (SUVmax) was 1.5; SUVmax lesion/SUVmax liver 1.0, and SUVmax/ SUV mean liver 1.5. Biopsy from mediastinal and axillary region did not have LN structure and was positive for S-100 immunostaining, and patient was diagnosed as benign neurofibroma. We believe that there is no need for biopsy in lesions considered benign based on FDG-PET/CT parameters.

Evaluation of eight melanocytic and neural crest-associated markers in a well-characterised series of 124 malignant peripheral nerve sheath tumours (MPNST): useful to distinguish MPNST from melanoma?

The diagnosis of malignant peripheral nerve sheath tumour (MPNST) may be challenging, especially in the sporadic setting. Owing to the lack of specific histological criteria, immunohistochemical and molecular diagnostic markers, several differential diagnoses must be considered, especially melanoma. Indeed, although S100 protein usually stains melanoma, other melanocytic markers are often negative, especially in spindle cell/desmoplastic types. This pattern of immunoreactivity resembles that of some nerve-derived tumours such as MPNST. Owing to their different clinical behaviours and therapeutic implications, accurate identification of these two different tumours is crucial. S100, SOX10, KBA62, MITF, HMB45, Melan-A, tyrosinase PNL2 and BRAF-V600E immunostaining was performed in a pathologically and genetically well-characterised cohort of primary MPNST (n=124), including 66 (53%) NF1-associated tumours. Sox10 and KBA62 expression were found, respectively, in 102 (84%) and in 101 (83%) MPNST, whereas S100 was expressed in 64 cases (52%). We observed an increased loss of S100 with increasing histological grade (P=0.0052). We found Melan-A expression in 14% (n=17) of all MPNST, occurring in 82% (n=14) of cases in an NF1 context. Six per cent (n=8) of MPNST showed tyrosinase positivity, including seven (87%) NF1-associated. MITF expression was found in 10 (8%) MPNST. None expressed PNL2, HMB45 or BRAF-V600E. MPNST (in NF1 and a sporadic setting) can quite often be positive for Melan-A, tyrosinase and MITF. Pathologists should be cognisant of these exceptions to prevent confusion with melanoma.

Spinal cord anaplastic meningioma with extra-neural metastasis in a cat

ABSTRACT: Meningiomas are the most frequent neoplasms involving the brain in dogs and cats, and are occasionally observed in the spinal cord. They cause compression of the central nervous system; however, do not infiltrate the neuropile and rarely metastasize to other organs. The present study describes a case of anaplastic spinal meningioma with extra neural metastasis in a 20 years-old cat. Clinically, the feline presented a clinical history of 120 days with paresis of the hind limbs and loss of the tail’s movements, with subsequent death. At necropsy, there was an irregular and soft whitish mass involving the meninges from the lumbar intumescence to the sacral region of the spinal cord. Similar white nodular masses were observed in the lungs, liver and kidneys. Microscopically, both were composed of a poorly limited and infiltrative neoplastic proliferation composed by spindle, round and epithelioid cells, with a high cellular pleomorphism. On IHC, there was a severe immunostaining for vimentin and S100. Histopathologic and IHC analysis are important tools for definitive diagnosis of meningiomas in cats, and differentiation of other common neurologic disorders in these animals.

Emperipolesis and S100 expression may be seen in cutaneous xanthogranulomas: A multi-institutional observation.

Cutaneous Rosai-Dorfman disease (RDD) can be difficult to distinguish from other non-Langerhans cell histiocytoses, particularly xanthogranuloma (XG). Pathologists use S100 immunoreactivity, abundant plasma cells, and the presence of emperipolesis to distinguish RDD from XG. However, S100 expression has been reported in XG and, in practice, we have occasionally observed emperipolesis in cases that were otherwise clinically and pathologically consistent with XG. We present 10 cases of XG with emperipolesis and variable S100 immunoreactivity. Histologically, 7 cases were most in keeping with XG, and a histologic differential of XG versus RDD was raised in the remaining 3 cases. All 10 cases were clinically consistent with XG. Notably, none of these cases showed abundant plasma cells. Nine cases showed variable S100 immunostaining, ranging from focal/weak expression, to focal/strong, diffuse/moderate, and diffuse/strong expression. Histiocytes in all cases were CD68 positive and CD1a negative. We conclude that emperipolesis and S100 expression in a skin biopsy cannot reliably distinguish XG from cutaneous manifestations of RDD. Clinical correlations are essential, as are histologic clues to a diagnosis of classic XG that include an abundance of foamy mononuclear cells, Touton giant cells, and an absence of pale-stained histiocytes, abundant plasma cells, fibrosis, or vascular proliferation.

Effects of sunitinib on immunoreactivity of vimentin, E-cadherin and S100 in kidneys of streptozotocin induced diabetic mice

Diabetes mellitus (DM) affects many organs including kidney. Tyrosine kinase can cause hypoglycemia and sunitinib is an inhibitor of tyrosine kinase. We investigated the possible effects of sunitinib on the kidney of streptozotocin (STZ) induced type 1 diabetic mice. We used 28 CD 1 type male mice divided into four groups of seven. Type 1 diabetes was induced by injection of STZ. Group 1 was the untreated control. Group 2 comprised non-diabetic mice + sunitinib. Both groups 1 and 2 exhibited normal blood glucose levels. Group 3 comprised STZ treated diabetic mice + saline. Group 4 were diabetic mice + sunitinib treatment. Kidneys were removed after 8 weeks. The immunoreactivities of vimentin, E-cadherin and S100 were assessed. Immunostaining of vimentin, E-cadherin and S100 was located in both the glomeruli and tubules of the kidney. We found that the number of vimentin and E-cadherin positive glomeruli and tubules were increased after sunitinib treatment compared to saline treated diabetic mice. The number of vimentin labeled tubules was decreased in the sunitinib treated group compared to diabetic + saline groups. Differences in the number of S100 positive tubules and glomeruli between groups 3 and 4 were not statistically significant. The effect of sunitinib on experimental diabetic mice appears to be related to levels of vimentin, E-cadherin and S100 in the glomeruli and tubules of the kidney, and sunitinib may protect against renal damage from DM.

Study of S100 Immunostaining in Demonstrating Neural Granulomas in Paucibacillary Leprosy.

Context:Neural granulomas are hallmark of leprosy. Challenges faced in diagnosing paucibacillary leprosy include: (i) Difficult visualization of nerve twigs on hematoxylin and eosin (H and E) sections due to their small size and (ii) Paucity of organisms on acid–fast bacilli stain.Aims:(1) This study aimed to test the role of S100 immunostain in demonstrating neural granulomas in skin biopsies of paucibacillary leprosy, (2) to compare morphology of S100 staining of nerves inside granulomas among clinicohistologically defined different types of leprosy, and (3) to test whether the pattern of S100 immunostaining can distinguish nerve fragmentation/destruction from a normal intact nerve in skin biopsy.Materials and Methods:Sixty four diagnosed cases of leprosy were included in this study. Five skin biopsies with no significant pathology (for studying intact nerve) and nine nonleprosy cutaneous granulomas were also studied.Results:(i) In demonstrating neural granuloma, sensitivity of H and E was 48.27% and that of S100 was 100%, (ii) Morphology of nerve fragments on S100 stain for cases of leprosy was fragmented and infiltrated in 37, intact and infiltrated in 19, reduced, fragmented, and infiltrated in seven, and absent in one, (iii) There was a significant difference (P <0.001) in the pattern of staining of S100 on intact nerve and nerves involved by granuloma in leprosy, and (iv) The probability to differentiate between leprosy and nonleprosy granuloma was statistically significant (P <0.001).Conclusion:S100 immunostaining showed to be an effective adjuvant to histopathology in diagnosing paucibacillary leprosy and differentiating it from nonleprosy cutaneous granuloma.

Effect of selective serotonin reuptake inhibitors (SSRIs) versus estradiol administration on anterior pituitary cell population and possible regenerative capacity in ovariectomized adult albino rats

ABSTRACTBackground: Reproductive ageing in women and the hormonal changes that occur during the onset of human menopause have been ascribed solely to ovarian failure and oocyte depletion. However, some studies have shown the central nervous system to be the major regulator of age-related reproductive dysfunction. Moreover, it has been postulated that the pituitary gland plays a key role in the menopausal process. Estradiol is a form of estrogen, a female sex hormone produced by the ovaries. Estradiol is used to treat symptoms of menopause such as hot flashes, and vaginal dryness, burning, and irritation. On the other hand, selective serotonin reuptake inhibitors (SSRIs) ease depression by increasing levels of serotonin in the brain.Aim of work: Thus, it became the aim of the present study, to elucidate the effect of SSRIs versus estradiol in ovariectomized rats on the overall anterior pituitary cell population with special emphasis on the Folliculo-stellate (FS) cells.Material and Methods: Thirty adult female Albino rats, ageing 3-4 months and 140-170 gm body weight were used in the present study. They were divided into 4 groups as follows:Group A (control group): further subdivided into 2 subgroups each including 6 rats. A1: rats were left untreated throughout the experiment. A2: rats were left untreated then received 2ml subcutaneous (s.c.) sesame oil injection daily for one week prior to sacrifice. In the remaining 3 groups (6 rats each), the ovaries were ectomized and rats were left for five months to mimic estrogen-depletion models. Then; Group B: 6 rats were used as an ovariectomy model. Group C: 6 rats received 40μg/kg body weight estradiol by s.c. injection daily for one week prior to sacrifice. Group D: 6 rats received 10mg/kg fluoxetine at a single dose/day by feeding tube for one week prior to sacrifice.Results: In the ovariectomized rats, there was loss of structural organization and an apparent decrease of cell population. Widespread vacuolations and cellular degeneration were also observed. An improved cellular architecture and cell population within pars distalis were seen with the administration of both estradiol and fluoxetine. Semithin sections confirmed these results. Immunostaining for the protein S-100 showed an apparent decrease in the distribution of the protein S-100 expression within the FS cells in ovariectomized rats that was significantly increased in response to estradiol and fluoxetine.Conclusion: Ovariectomized rats revealed degeneration of the anterior pituitary cell population and decreased expression of protein S-100 in the pars distalis indicating decreased population of FS cells. Such effects were reversed by either estradiol or fluoxetine administration. This might suggest the added effect of both drugs if administered together on the improvement of anterior pituitary cell population as well as FC cells.

Immunofluorescence and confocal microscopy for ex-vivo diagnosis of melanocytic and non-melanocytic skin tumors: A pilot study.

Ex-vivo confocal laser scanning microscopy (ex-vivo CLSM) offers rapid examination of freshly excised tissue. During the conventional examination immunohistochemistry enables to distinguish various cell types. The possibility of immunofluorescent techniques could enhance the accuracy of the diagnosis performed by ex-vivo CLSM. The tissue probes from various skin tumors were stained with FITC-labeled S-100A10, Melan-A and anti-Ber-EP4 antibodies before examination with ex-vivo CLSM in the fluorescence and reflectance modes. Results were compared to negative controls and conventional histopathology. The staining protocols were evaluated by establishing a scoring system according to the signal intensity found in ex-vivo CLSM. S100 immunostaining was successful in 55.6%. Dilution of 1:200 resulted in the best possible evaluation of the tumor. The best suitable protocol was protocol B (phosphate buffered saline [PBS], without blocking agent). Melan A immunostaining was positive in 66.7%, the best dilution was 1:500 and protocol B (PBS, without blocking agent) was the most suitable. Ber-EP4 immunostaining presented a signal in 85.7%, the best dilutions were 1:200 and 1:500 and protocol A (PBS, with blocking agent) showed most optimal results. The use of fluorescent-labeled antibodies in ex-vivo CLSM is possible and could improve intraoperative diagnostics of skin tumors.

Role of S-100 Immunostain as An Auxiliary Diagnostic Aid in Leprosy

Histopathologic diagnosis of leprosy is difficult when Bacillary Index (BI) is zero and neural involvement are not easily identifiable on routine Hematoxylin and Eosin stain. This study was undertaken to study the role of S-100 immunostaining in demonstrating different patterns of nerve involvement in various types of leprosy. Thirty one skin biopsies with clinico-histopathologic diagnoses of leprosy over a period of two years were included in the study. Ten cases of non-lepromatous granulomatous dermatoses (including eight cases of lupus vulgaris and two cases of erythema nodosum) were used as controls. Tissue sections from all cases and controls were stained with Hematoxylin and Eosin (H&E) stain, Fite stain and S-100 immunostain. The H&E stained slides were used to study the histopathological features, Fite stained slides for Bacillary Index and S-100 for nerve changes. Neural changes could be demonstrated in the entire spectrum of leprosy using S-100 immunostaining. The most common pattern of nerve destruction in the tuberculoid spectrum was fragmented and infiltrated whereas lepromatous spectrum showed mostly fragmented nerve twigs. Intact nerves were not detected in any of the leprosy cases. S-100 immunostain is a useful auxiliary aid to the routine H&E stain in the diagnosis of leprosy especially tuberculoid spectrum and intermediate leprosy.

High prevalence of MiTF staining in undifferentiated pleomorphic sarcoma: caution in the use of melanocytic markers in sarcoma.

The diagnosis of undifferentiated pleomorphic sarcoma (UPS) may be challenging, as other lesions with undifferentiated spindle cell morphology must be excluded, including melanoma. Microphthalmia-associated transcription factor (MiTF) stains naevi and epithelioid melanomas, as well as some mesenchymal neoplasms. The aim of this study was to evaluate the prevalence of MiTF and melanocytic markers in UPS and a subset of atypical fibroxanthoma (AFX). MiTF, SOX10, Melan-A, HMB45 and S100 immunostaining was performed on resection specimens from 19 UPSs and five AFXs. Next-generation sequencing of 50 genes was performed in UPSs to exclude dedifferentiated melanoma. In 17 of 19 UPSs (89%), tumour cells showed nuclear positivity for MiTF that was not eliminated by casein block. Three showed focal nuclear staining for HMB45, which was eliminated by casein block. One showed focal nuclear vacuole staining for S100 with red but not brown chromogen. None expressed SOX10 or Melan-A. Mutational analysis of 15 UPSs with adequate DNA showed no mutations within hotspot regions of BRAF, KIT, or NRAS. Four of five AFXs (80%) stained with MiTF; other markers were negative. There is a high prevalence of nuclear MiTF expression in UPSs (89%) and AFXs (80%). Rare UPSs showed non-specific nuclear HMB45 or S100 staining. These findings argue against using MiTF in isolation to differentiate between UPS or AFX and melanoma, and caution in interpreting focal staining for a single additional melanocytic marker. Casein block may eliminate non-specific staining. MiTF should be used to support a diagnosis of melanoma only if multiple melanocytic markers are positive.

Non-ocular melanomas in cats: a retrospective study of 30 cases.

Objectives The aim of the study was to describe the clinical outcome of 30 cats with non-ocular melanomas and to evaluate the association between clinical or pathological parameters and overall survival time. Methods The database of the animal histopathological laboratory of the National Veterinary School of Nantes (Oniris, Nantes, France) was retrospectively searched to identify cases of feline non-ocular melanomas between December 2009 and April 2014. For each case, clinical data, including signalment, location of the primary tumour, staging, treatment and outcome, were collected from the medical records or via interviews with referring veterinarians. Histological and immunohistochemical evaluation included mitotic index, cytonuclear atypias, junctional activity, Melan A and S100 immunostaining, and surgical margins. Univariate analysis to test the prognostic value of the different variables was performed by the Kaplan-Meier product limit method using the log-rank test of significance. Results Thirty cats were included in the study. Eleven had a cutaneous non-auricular melanoma, six had a tumour located on the pinna and 13 had a tumour in the oral cavity. Cats with auricular melanomas were significantly younger than cats with tumours in other locations. Location and presence of clinical signs were not of prognostic significance, but the achromic phenotype was significantly associated with a poorer prognosis. Twenty cats were treated with surgery and survived significantly longer than cats that received only medical treatment or that did not receive any treatment. According to our data, mitotic index, cytonuclear atypias, junctional activity, Melan A or S100 expression, and surgical margins were not associated with survival. Conclusions and relevance We show for the first time, in a large series, that the auricular form of melanoma affected significantly younger cats than other extraocular forms. Most feline non-ocular melanomas are malignant and achromic tumours are associated with a poorer prognosis. According to this study, surgery should be considered as a priority.

Lower numbers of mechanoreceptors in the posterior cruciate ligament and anterior capsule of the osteoarthritic knees.

Impaired proprioception accuracy of the knee has been proposed as a local factor in the onset and progression of knee osteoarthritis. Patients with decreased numbers of mechanoreceptors could be more likely to develop arthrosis due to a loss in proprioception of the joint. We aimed to identify and quantify the mechanoreceptors of the posterior cruciate ligament (PCL), the anterior capsule (AC) and the medial meniscocapsular junction (MCJ) in knee arthrosis. PCLs, ACs and MCJs were harvested from 30 patients with Kellgren and Lawrence grades 3 and 4 osteoarthritis (OA), and ten knees taken from five cadavers without OA were used as a control group. PCL degeneration was evaluated with haematoxylin & eosin, and the types and numbers of mechanoreceptors were evaluated using S100 immunostaining. The patient ages in the OA and control groups (n.s.) did not differ. PCL degeneration was more severe in the gonarthrosis group than in the control group (p=0.04). The numbers of Golgi corpuscles, Ruffini corpuscles, free nerve endings, total nerve endings and small vessels of the PCL were low in the OA group, as were the numbers of Golgi corpuscles, free nerve endings and total nerve endings of the AC. No significant correlation was found regarding the mechanoreceptors of the MCJ between the two groups. The numbers of mechanoreceptors in patients with OA were low in the PCLs and ACs. A loss in proprioception could be a local risk factor in OA. The proprioceptive impact of preserving PCL while performing total knee arthroplasty may not be exaggerated as its thought. Prognostic study, Level I.

Cutaneous spindle cell squamous cell carcinoma.

Dear Editor: Spindle cell squamous cell carcinoma (SpSCC) is a rare variant of squamous cell carcinoma (SCC). Despite having clinical attributes that overlap conventional SCC, these lesions are pathologically distinct and are comprised of spindled cells that infiltrate the dermis as single cells or cohesive nests; that lack features of keratinization. SpSCC most commonly occurs in the larynx, and less often in the hypopharynx, oropharynx, and nasal cavity1. It is extremely rare to find SpSCC confined to the cutaneous lesion, and only three cases have previously been reported in Korea. A 73-year-old woman presented with a 1-year history of a pruritic, solitary mass on the face. Physical examination revealed an irregular-shaped, erythematous, firm, fixed mass with a yellowish crust on her left upper perioral area. The mass was 1.3 cm in diameter and was slowly expanding (Fig. 1). The patient had a history of a wide excision of basal cell carcinoma on her nose 2 years previously, and no relapse has been observed. Fig. 1 (A, B) Solitary, 1.3 cm-sized, irregular-shaped, erythematous, firm mass with a yellowish crust on the left upper perioral area. Histologic examination of the lesion showed spindle-shaped cells with hyperchromatic nuclei infiltrating the dermis in a whorl-like pattern (Fig. 2). Furthermore, immunohistochemical investigation revealed the specimen was positive for cytokeratins (34βE12, CK5/6, AE1/3) and vimentin, but was negative for smooth muscle actin (SMA), S-100, and CD68. Through histologic features and immunohistochemical evaluation, she was diagnosed with SpSCC. The lesion was surgically removed 13 months previously and no relapse has been observed. Fig. 2 (A) Diffuse dermal infiltrates of spindle cells (HE B: ×200, C: ×400). (D) Positive immunostaining for 34βE12, ... Cutaneous SpSCC presents as a raised or exophytic nodule accompanied by spontaneous bleeding and central ulceration similar to conventional SCC2. It is usually confined to sun-damaged sites such as the head, neck, chest, and upper extremities or areas that have received prior ionizing radiation2,3. Although the rarity of these tumors makes difficult to study patient survival rates, the literature suggests an overall prognosis similar to that of conventional SCC. SpSCC must be distinguished from other spindle cell lesions such as atypical fibroxanthoma (AFX), spindle cell/desmoplastic melanoma, cutaneous leiomyosarcoma, and scars. Immunohistochemistry has become the essential method in the pathologic workup of these tumors. The spindle cells in SpSCC stained positively for one or more of the cytokeratins (34βE12, AE1/3, cam 5.2, low molecular weight keratin) and the mesenchymal marker, vimentin. Each of these neoplasms stained negatively for S-100, CD68, and SMA; whereas AFX showed positivity for CD68, but lacked keratin and S-100. The spindle cell melanomas showed a connection with the epithelium that was contiguous with similar junctional cells possessing cytoplasmic melanin and S-100 immunostaining, but lacking keratins. The leiomyosarcomas showed positivity with SMA and vimentin, and were negative for keratins and S-100. The scars were negative for all immunohistochemical stains4. Cutaneous SpSCC is so rare subtype of SCC that pathophysiology, prognostic factors, and metastatic risk are not well-established. It is known that SpSCCs that are associated with radiation, burn scars, and immunosuppression may correlate with aggressive clinical courses5. Further studies of this rare entity are needed to establish its biological behavior, and the accumulation of more case reports will aid in determining a precise prognosis.

Atypical Fibroxanthoma of Scalp: A Paradoxical Benign Tumour.

Atypical fibroxanthoma (AFX) is a recently described soft tissue tumour by World Health Organization as a benign tumour of uncertain differentiation, occurring on sun exposed skin in elderly individual [1]. The bizarreness as well as marked atypia seen in the cells raises a first impression of malignant tumour, whereas it is rarely so. It has a male predominance (70%) with an average age of presentation of 71.9 years, ranging from 29–91 years [2]. An 81-year-old male presented with hard nodular scalp swelling since 7 to 8 years with a rapid size increase since 3 months. On examination there was a nodulo-ulcerative lesion measuring 5cm x 3cm on scalp with bleeding edges. He did not have any other cutaneous lesion or lymphadenopathy. Excisional biopsy done outside was reported as sebaceous carcinoma. The patient was referred to our hospital for further management. On review of biopsy slides, the tumour cells were spindled, plump to epithelioid with marked pleomorphism, arranged in haphazard, vaguely fascicular or storiform patterns [Table/Fig-1a]. Tumour cells had hyperchromatic and multilobulated bizarre nuclei with scattered multinucleate tumour giant cells. Some cells of the lesion contained vacuolated and lipid-containing cytoplasm similar to xanthoma raising doubts of sebaceous carcinoma, as diagnosed outside [Table/Fig-1b]. On extensive IHC work up, the tumour cells were positive for Vimentin (Dako;V9) [Table/Fig-1c], CD68 (Leica;514H12), CD10 (Dako;56C6) [Table/Fig-1d] and negative for Cytokeratin (Biogenix;AE1+AE3) [Table/Fig-1e], EMA (Dako, E29), SMA (Dako;1A4), S 100 (Dako;IS504), Desmin (Dako;D33), Caldesmon (Dako; H-CD) and HMB 45 (Dako;HMB45) [Table/Fig-1f]. A final diagnosis of atypical fibroxanthoma was made. [Table/Fig-1]: Histopathological examination showing large bizarre cells with abundant foamy cytoplasm and atypical mitosis (HE b) 400x). Immunohistochemistry showing positivity for Vimentin (c), CD10 (d) and negativity for Cytokeratin (e), HMB45 ... Making a diagnosis of atypical fibroxanthoma is challenging and the diagnosis should be made by exclusion of other differential diagnoses after applying the stringent histological criteria and a broad panel of immunostains. Cutaneous carcinomas and melanoma must be ruled out by immunohistochemistry. Absent immunostaining for cytokeratins, S100 and HMB45 in AFX are helpful for excluding sebaceous carcinoma along with squamous cell carcinoma and malignant melanoma. Other differentials are malignant fibrohistiocytoma, atypical Fibrous Histiocytoma /dermatofibroma with monster Cells and pleomorphic fibroma [Table/Fig-2]. By definition, in AFX tumour cells lack expression of S100, cytokeratin, CD34, desmin and h-caldesmon. Previously our case was misdiagnosed as sebaceous carcinoma due to pleomorphism, abundant clear to foamy cytoplasm and bizarre pleomorphic nuclei. CD10 is a useful marker for AFX and is positive in 95%–100% cases of AFX [2]. A histiocytic marker CD 68 is positive in more than half of cases [3]. AFX shows a very good prognosis after surgical excision [4]. Reports of metastasis are very rare, and recurrence is uncommon [5]. Distinction from high grade sarcoma is crucial to prevent inappropriate aggressive therapy. [Table/Fig-2]: Differential diagnoses of atypical fibroxanthoma

Immunohistochemical and histopathological characters of renal mesenchymal tumor in a Wistar rat

A 15 weeks old male Wistar rat was having abdominal distention. Postmortem examination revealed a highly expansile mass with large cystic cavities and nodular growths on the abdominal wall. The tumor mass caused enlargement of the abdomen and nearly replaced the right kidney. The lesion was diagnosed as renal mesenchymal tumor by histomorphological examination which was aided by immunostaining. The distinctive feature of the present case was that the tumor was positive S100 and cytokeratin immunostaining, which has not been reported earlier.

Fibrosis, adipogenesis, and muscle atrophy in congenital muscular torticollis.

In the traditional view, muscle atrophy and interstitial fibrosis were regarded as the basic pathological features of congenital muscular torticollis (CMT). But in the ultrastructure study, the mesenchyme-like cells, myoblasts, myofibroblasts, and fibroblasts were found in the proliferation of interstitium of CMT. To investigate the characteristics of pathological features and the mechanisms of muscle atrophy in CMT, we retrospectively reviewed the medical records of 185 CMT patients from July 2009 to July 2011 in Shenzhen Children's Hospital in China and performed pathological studies. According to age, the 185 CMT patients were divided into 4 groups. All resected surgical specimens were processed for hematoxylin and eosin staining and Masson trichromic staining. Sudan III staining was used for frozen sections, whereas immunohistochemical staining for S-100, calpain-1, ubiquitin, and 20S proteasome was carried out on 40 CMT specimens. Eight adductor muscle specimens from 8 patients with development dysplasia of the hip were taken as control group in the immunohistochemical staining. By Masson trichromic staining, the differences in the percent area of fibrous tissue in each CMT groups were significant. In Sudan III staining and immunostaining for S-100, adipocyte hyperplasia was the pathological feature of CMT. Moreover, compared with controls, most atrophic muscle fibers in CMT specimens were found to show strong immunoreactivity for calpain-1, ubiquitin, and 20S proteasome. With increasing age, fibrosis peaked at both sides and it was low in middle age group. Adipocytes increased with age. The characteristics of pathological features in CMT are changeable with age. The calpain and the ubiquitin–proteasome system may play a role in muscle atrophy of CMT. In the CMT, adipogenesis, fibrogenesis, and myogenesis may be the results of mesenchyme-like cells in SCM (sternocleidomastoid muscle). In conclusion, the present study furthermore supports maldevelopment of the fetal SCM theory for etiology of CMT.

Pancreatic Fibromyxoid Sarcoma: A Rare Variant

Introduction: A 53-year-old man presented to our emergency department with 3 months of dull left flank pain. Initial evaluation demonstrated normal physical exam and lab values; he was discharged with pain medication. The pain persisted and he returned to the ED. A CT scan showed a calcified mass in the body of his pancreas. Labs at this time showed normal liver tests but his lipase was mildly elevated at 65 units/L. Endoscopic ultrasound (EUS) was performed and demonstrated a 3.7 x 3.2 cm calcified, hypoechoic mass with associated upstream dilation of the pancreatic duct to 9 mm. FNA was nondiagnostic. At this point, the differential included carcinoma, neuroendocrine neoplasm, gastrointestinal stromal tumor, epithelioid angiomyolipoma, solid pseudopapillary neoplasm, fibromatosis of the pancreas, or focal chronic pancreatitis. Surgical consultation was requested and distal pancreatectomy was recommended. A 7-cm tumor was found in the pancreatic body and tail. Frozen sections showed carcinoma most consistent with a neuroendocrine tumor. Histology showed vascular invasion into the splenic vessels without evidence of lymph system invasion. H&E sections revealed a mild to moderately cellular lesion composed of spindled and epithelioid cells in a hyalinized matrix. There was focal mature bone within tumor, but no malignant epithelial component. The tumor invaded pancreatic parenchyma extensively. Immunostains for CD34 and GLUT-1 showed patchy positivity within tumor. The tumor was negative for cytokeratin 7, cytokeratin AE1/AE3, epithelial membrane antigen, desmin, actin, and S-100 immunostains. A MUC-4 immunostain was strongly positive. The combinations of the histological and immunohistochemical findings are consistent with a low-grade fibromyxoid sarcoma (LGFMS) with sclerosing epithelioid fibrosarcoma (SEF) variant. SEF is a variant of LGFMS. These tumors are often found in the extremities and less often in the groin, trunk, and neck. Abdominal LGFMS/SEFs are almost exclusively been reported in the retroperitoneum. These rare tumors were first identified as a unique sarcoma in 1995 and approximately 100 individual cases have been identified. Only 1 case of LGFMS/SEF of the pancreas exists in the literature. We provide another case. Based on a small patient case series of LGFMS/SEF, local recurrence is seen in as many as 37-48% of cases with a distant metastasis rate of 36=60% and mortality rates are around 35%. Our case has invasion of the splenic vein, but to date there is no evidence of metastatic disease after undergoing primary resection with external beam radiation. He continues to undergo quarterly surveillance imaging.

Schwann-like cells seeded in acellular nerve grafts improve nerve regeneration.

BackgroundThis study evaluated whether Schwann-like cells (SLCs) induced from bone marrow-derived mesenchymal stem cells (BM-MSCs) transplanted into acellular nerve grafts (ANGs) could repair nerve defects compared with nerve isografts and ANGs with BM-MSCs.MethodsBM-MSCs extracted, separated and purified from the bone marrow of rats, and some of the BM-MSCs were cultured with mixed induction agents that could induce BM-MSCs into SLCs. Either SLCs or BM-MSCs were seeded onto 10-mm ANGs, and the isografts were chosen as the control. The walking-track test, tibialis anterior muscle weight measurement, electrophysiological examination, toluidine blue staining, transmission electron micrographs and immunostaining of S-100 and VEGF in these three groups were evaluated in a 10-mm rat sciatic injury-repair model.ResultsThe walking-track test, tibialis anterior muscle weight measurement and electrophysiological examination of the sciatic nerve suggested the groups of ANGs with SLCs and isografts obtained better results than the BM-MSC group (P < 0.05). Meanwhile, the results of the SLCs and isograft groups were similar (P > 0.05). All the histomorphometric analyses (toluidine blue staining, transmission electron micrographs and immunostaining of S-100 and VEGF) showed that there were more regenerating nerve fibers in the group of ANGs with SLCs than the BM-MSCs (P < 0.05), but there was no significant difference between the SLC and isograft groups (P > 0.05).ConclusionsSLCs seeded in ANGs and isografts show better functional regeneration compared with BM-MSCs seeded in ANGs. Additionally, SLCs combined with ANGs present almost the same outcome as the isografts. Therefore, SLCs with ANGs can be a good choice in nerve defect repairs.

Effects of cerebrolysin on rat Schwann cells in vitro

Although the peripheral nervous system (PNS) is capable of regeneration, these processes are limited. As a potential means to augment PNS regeneration, the effects of cerebrolysin (CL), a proteolytic peptide fraction, were tested in vitro on Schwann cell (SC) proliferation, stress resistance, phagocytic and cluster-forming capacity. Primary SC/fibrocyte co-cultures were prepared from dorsal root ganglia of 5–7-day-old rats. SCs were subjected to mechanical stress by media change and metabolic stress by serum glucose deprivation (SGD). Cell survival was assessed using MTT test. SC proliferation was determined by counting BrdU-labeled cells. SC clustering was studied by ImageJ analysis of S100 immunostaining. Wallerian degeneration (WD) was evaluated by measuring acetylcholine-esterase staining within sciatic nerves in vitro. It was found that CL caused no effect on MTT turnover in the tested doses. CL inhibited SC proliferation in a dose-dependent manner. Media change and additional SGD stress inhibited SC clustering. CL enhanced the reorganization of SC clusters and was able to counteract SGD-induced cluster defects. Moreover, CL accelerated WD in vitro. CL was able to enhance the functions of SCs that are relevant to nerve regeneration. Thus, our findings suggest that CL may be suitable for therapeutic usage to enhance PNS regeneration/reconstruction.