Fascicular Pattern Research Articles

Assessing the Performance of Morphologic and Echogenic Features in Median Nerve Ultrasound for Carpal Tunnel Syndrome Diagnosis.

To assess the feasibility of using ultrasound (US) image features related to the median nerve echogenicity and shape for carpal tunnel syndrome (CTS) diagnosis. In 31 participants (21 healthy participants and 10 patients with CTS), US images were collected with a 30-MHz transducer from median nerves at the wrist crease in 2 configurations: a neutral position and with wrist extension. Various morphologic features, including the cross-sectional area (CSA), were calculated to assess the nerve shape. Carpal tunnel syndrome commonly results in loss of visualization of the nerve fascicular pattern on US images. To assess this phenomenon, we developed a nerve-tissue contrast index (NTI) method. The NTI is a ratio of average brightness levels of surrounding tissue and the median nerve, both calculated on the basis of a US image. The area under the curve (AUC) from a receiver operating characteristic curve analysis and t test were used to assess the usefulness of the features for differentiation of patients with CTS from control participants. We obtained significant differences in the CSA and NTI parameters between the patients with CTS and control participants (P < .01), with the corresponding highest AUC values equal to 0.885 and 0.938, respectively. For the remaining investigated morphologic features, the AUC values were less than 0.685, and the differences in means between the patients and control participants were not statistically significant (P > .10). The wrist configuration had no impact on differences in average parameter values (P > .09). Patients with CTS can be differentiated from healthy individuals on the basis of the median nerve CSA and echogenicity. Carpal tunnel syndrome is not manifested in a change of the median nerve shape that could be related to circularity or contour variability.

LEIOMYOSARCOMA IN THE LATERAL BORDER OF THE TONGUE: A RARE CASE REPORT

Leiomyosarcoma is a rare mesenchymal malignant neoplasm, of which 3% to 10% of cases occur in the head and neck region. The leiomyosarcoma of the tongue is a very rare tumor with only 10 cases described in the literature. This work reports a case of oral leiomyosarcoma arising in the lateral border of the tongue of a 78-year-old man. Clinical examination showed a well-demarcated, firm and painful nodule measuring about 3 cm in diameter. After incisional biopsy, microscopic analysis showed the spindle-shaped tumor cells were arranged in an interlacing fascicular pattern and contained oval to elongated blunt-ended (cigar-shaped) nuclei. More than 10 mitoses per high-power field were counted. Immunohistochemical examination displayed that tumor cells were strongly positive to H-caldesmon, actin, and vimentin and negative to S100, establishing the final diagnosis of leiomyosarcoma. The patient was referred for oncologic treatment.

Radiomics of peripheral nerves MRI in mild carpal and cubital tunnel syndrome.

To assess the discriminative power of radiomics of peripheral nerves at 1.5T MRI, using common entrapment neuropathies of the upper limb as a model system of focal nerve injury. Radiomics was retrospectively done on peripheral nerve fascicles on T1-weighted 1.5T MRI of 40 patients with diagnosis of mild carpal (n = 25) and cubital tunnel (n = 15) syndrome and of 200 controls. Z-score normalization and Mann-Whitney U test were used to compare features of normal and pathological peripheral nerves. Receiver operating characteristic analysis was performed. A total of n = 104 radiomics features were computed for each patient and control. Significant differences between normal and pathological median and ulnar nerves were found in n = 23/104 features (p < 0.001). According to features classification, n = 5/23 features were shape-based, n = 7/23 were first-order features, n = 11/23 features were classified as gray level run length matrix. Nine of the selected features showed an AUC higher that 0.7: minimum AUC of 0.74 (95% CI 0.61-0.89) for sum variance and maximum AUC of 0.90 (95% CI 0.82-0.99) for zone entropy. Features analysis demonstrated statistically significant differences between normal and pathological nerve. The results suggested that radiomics analysis could assess the median and ulnar nerve inner structure changes due to the loss of the fascicular pattern, intraneural edema, fibrosis or fascicular alterations in mild carpal tunnel and mild cubital tunnel syndromes even when the nerve cross-sectional area does not change.

Proceedings From the Clinical and Scientific Innovations in Oral and Maxillofacial Surgery Conference 2019

Proceedings From the Clinical and Scientific Innovations in Oral and Maxillofacial Surgery Conference 2019

Nodular lesion in the tongue: A rare case of low grade myofibroblastic sarcoma

Low grade myofibroblastic sarcoma is an atypical myofibroblastic malignant neoplasm that rarely affects the oral cavity and presents a challenging histological diagnosis. Here we report the case of a 38-year-old woman who had a nodular and symptomatic lesion on the lateral border of the tongue. After the biopsy, the histopathological analysis revealed a spindle cell lesion with fascicular and storiform pattern. We performed immunohistochemical analysis that showed intense labeling for vimentin, smooth muscle actin and moderate labeling for calponin and S-100. We emphasize the rarity of low grade myofibroblastic sarcoma such as a nodular lesion on the tongue and the need for accurate diagnosis.

Malignant Gastrointestinal Neuroectodermal Tumor

A malignant gastrointestinal neuroectodermal tumor (GNET) is rare, and it is therefore yet to be completely understood. This study aimed to present the clinicopathologic features of GNET, including treatment information. We included 19 patients with GNET with a mean tumor size of 4.2 cm. The most common site of tumor origin was the small intestine (57.9%), followed by the stomach (15.8%), colon (10.5%), ileocecal junction (5.3%), lower esophagus (5.3%), and anal canal (5.3%). Microscopically, the tumors were composed of epithelioid cells with eosinophilic or clear cytoplasm arranged in nest, sheet-like, papillary, or pseudoalveolar patterns and/or spindle tumor cells with eosinophilic cytoplasm arranged in a fascicular pattern. Immunohistochemically, the tumor cells stained positively for S100 (19/19,100%), SOX10 (14/15, 93.3%), vimentin (17/17, 100%), synaptophysin (Syn) (7/17, 41.2%), CD56 (4/13, 30.8%), CD99 (1/5, 20%), and CD117 (1/15, 6.7%), and negatively for HMB45, Melan A, DOG1, CD34, AE1/AE3, CAM5.2, chromogranin A, smooth muscle actin, and desmin. In total, 14/15 (93.3%) cases showed split Ewing sarcoma breakpoint region 1 gene (EWSR1) signals consistent with a chromosomal translocation involving EWSR1. Within a mean follow-up of 29.7 months (range: 3 to 63 mo), 2/15 (13.3%) patients died of disease, 5 (33.3%) were alive with disease, and 8 (53.3%) had no evidence of disease. Two and 1 patients showed partial response to apatinib and anlotinib, respectively. In conclusion, GNET has distinctive morphologic, immunohistochemical, and molecular genetic features and should be distinguished from other gastrointestinal tract malignancies. Apatinib and anlotinib might be effective for the treatment of advanced GNET and could prolong patient survival.

Unusual Left Atrium and Pulmonary Vein Mass: Correlation of Imaging and Immunohistochemical Stains

Abstract Introduction Intimal sarcoma derived from the pulmonary vein and left atrium is an extremely rare and highly aggressive soft tissue neoplasm. We report a 21-year-old woman with a large filling defect in the pulmonary vein. The lesion extended into the left atrium mimicking a thrombus or a myxoma. Case History A 21-year-old woman presented with progressively worsening weakness, orthopnea, and exertional dyspnea of 2 weeks’ duration. Chest CT scan revealed a large left atrial mass, measuring 8.6 × 4.9 cm, which invaded the right lower lobe of lung and inferior pulmonary vein. Patient underwent right lower lobectomy and surgical resection of the left atrial mass and pulmonary vein. Result Histologic examination showed a highly cellular, cytologically malignant spindle cell neoplasm in a fascicular pattern. The lesional cells had hyperchromatic tapering nuclei and indistinct cytoplasm. There were numerous mitoses, focal necrosis, and predominantly myxoid stroma. The histologic features suggested the possibility of a myxofibrosarcoma or an intimal sarcoma. The lesional cells were immunoreactive for MDM2 and CDK4, consistent with amplification of the genes on the long arm of chromosome 12. Additionally, the lesional cells were vimentin, CD99, and BCL2 positive while nonimmunoreactive for S100, AE1/3, CD31, CD34, desmin, SMA, MyoD1, myogenin, MPO, and calretinin. Immunohistochemical staining for H3K27me3 was retained. These immunohistochemical findings supported the diagnosis of an intimal sarcoma. Conclusion Intimal sarcoma commonly involves the aorta and rarely presents as a pulmonary vein or atrial mass. Correlation of imaging and pathologic findings is critical, as intimal sarcoma can mimic a thrombus. Application of immunostains and cytogenetic studies are useful to distinguish intimal sarcoma from other cardiac sarcomas and myxoma of atrium.

Leiomyosarcoma: A Rare Tumor of the Vulva

Abstract Objective Primary sarcomas of the vulva are very rare malignancies, accounting for 1% to 3% of all gynecologic sarcomas. Leiomyosarcoma is the most common histologic type. They present with nonspecific symptoms, aggressive behavior, and high metastatic potential. Methods A 63-year-old female patient presented with a 6-month history of a slow-growing, painless vulvar mass at the right posterior fourchette. CT scan revealed an asymmetric, heterogeneous vulvar mass extending to the distal vagina, without lymphadenopathy or evidence of distant metastasis. Focal prominence of the uterus suggestive of leiomyoma was also noted, but primary uterine neoplasm with vulvar metastasis could not be excluded. The patient underwent wide local excision of the vulvar mass with hysterectomy and bilateral salpingo-oophorectomy. Results Gross examination of the vulvar specimen showed an ulcerated 2.1-cm solid white mass with irregular borders. Microscopically, the vulvar tumor consisted of a focally infiltrative spindle and pleomorphic neoplastic proliferation with interlacing fascicular pattern and increased mitotic activity up to 25/10 HPF, without necrosis or lymphovascular invasion. The tumor focally extended to resection margins. Immunohistochemically, the neoplastic cells were positive for SMA, ER, and desmin and negative for S-100 and cytokeratin AE1/AE3. These findings, in conjunction with the clinical presentation, were consistent with high-grade primary vulvar leiomyosarcoma. Radiation therapy was subsequently started. Conclusion Primary vulvar leiomyosarcomas are rare and secondary involvement by uterine primary should always be ruled out. In addition, these tumors can be mistaken clinically as benign processes such as Bartholin gland cysts, infectious granuloma, fibroma, or myoma. Hence, it is vital to consider vulvar sarcomas in the differential diagnosis of nonspecific vulvar lesions in order to avoid delay in diagnosis and treatment. The rarity of this diagnosis makes this case worth reporting.

PRIMARY MANDIBULAR UNDIFFERENTIATED SARCOMA. A CASE REPORT

Objective To present a primitive monophasic sarcoma of the mandible in a young male with spindle-cell predominant component and non-specific immunohistochemical phenotype. Uncertain origin sarcomas are a very complex and heterogeneous group of neoplasms, categorized by their undetermined histogenesis and peculiar morphological features; generally associated to a specific translocation. This type of sarcomas has not sufficient clinical and diagnostic information because its low frequency in this site. Case report A 23-year-old male presented with slow-progressive mobility and tooth loss associated with gingival enlargement in the third quadrant. Local examination showed a firm mass of approximately 5 × 4 cm in the body of the mandible. X-ray examination revealed an extensive ill-defined radiolucency on the left side of the mandibular body. CT-scan assessed bone and soft tissue infiltration. Hemimandibulectomy was performed and gross examination consisted of a solid nodular mass. Microscopically a monotonous spindle-cell lesion with fascicular pattern was observed, hypercellular areas and hemangiopericytoid-like vessels were the predominant component. The neoplastic cells displayed pleomorphic nuclear features with vesicular chromatin. A wide immuhohistochemical panel was performed showing reactivity for Calponin, CD68, CD99, Bcl-2, TLE-1, NSE, FLI-1, WT1, PTEN and 40% Ki67 index. Conclusion Despite of the high sensitivity, antibodies are not conclusive for an accurate diagnosis. Molecular techniques were required to establish this entity with great implication in patient management. Complete assesment of undifferentiated sarcomas should include clinical/radiological correlation, histopathology, immunohistochemical staining and genetic confirmation.

Primary intraosseous hybrid epithelioid schwannoma/perineurioma in the proximal tibia: a case report of benign hybrid neoplasm with local hypercellularity

BackgroundAs a new entity included in the 4th edition of the WHO classification of tumours of soft tissue and bone in 2013, hybrid peripheral nerve sheath tumours are benign composite neoplasms that demonstrate features of more than one type of nerve sheath tumour, with a wide age distribution and a predilection for superficial location. Those involving deep sites are relatively rare. To the best of our knowledge, only one case of primary intraosseous hybrid peripheral nerve sheath tumours has been documented. In this article, we report another case of hybrid peripheral nerve sheath tumours occurring in bone with different clinical, radiological and pathological features from those in the previously reported cases.Case presentationA 28-year-old female presented with a painful nodule in the right tibia. Radiological examination revealed an oval eccentric osteolytic lesion in the proximal tibia. Histologically, the circumscribed but unencapsulated lesion demonstrated biphasic cellular differentiation. Bland, small epithelioid cells arranged in clusters in the myxoid or collagenous stroma and inconspicuous spindle cells scattered in the hypercellular areas were suggested to originate from Schwann cells according to the detection of S100. Both the elongated spindle cells with thin, wavy nuclei and the spindle cells in fascicular or storiform pattern in hypercellular areas showed a positive immunoreaction for epithelial membrane antigen, indicating perineurial differentiation. Based on histological and immunochemical examinations, the patient was diagnosed with hybrid epithelioid schwannoma/perineurioma. The lesion was resected and has not recurred for 8 months since resection.ConclusionThe present case is the second primary intraosseous hybrid peripheral nerve sheath tumour to be reported. This is also the first reported intraosseous tumour composed of epithelioid schwannoma and perineurioma with hypercellularity, indicating diverse involvement sites and a wide range of histological features among hybrid peripheral nerve sheath tumours. Awareness of such diversity is critical for accurate diagnoses. The morphological overlap with other spindle and epithelioid cell neoplasms, especially pure peripheral nerve sheath tumours, requires that immunochemical and molecular examinations be used as objective tools to provide the necessary information for a differential diagnosis.

Clinicopathological features and prognosis of ALK-positive Spitz tumors

Objective: To investigate the clinicopathologic features and prognosis of ALK-positive Spitz tumors. Methods: Thirteen patients with ALK-positive Spitz tumors diagnosed at Shanghai Cancer Center, Fudan University from October 2016 to December 2017 were collected. All cases were routinely evaluated histopathological features in HE staining and detected ALK protein expression by immunohistochemistry. The ALK fusions of 7 cases were confirmed by fluorescence in situ hybridization (FISH).Follow-up data was collected. Results: The age of patients including 2 males and 11 females ranged from 4 to 47 years (mean 25 years). 12 patients were diagnosed with atypical Spitz tumors and 1 patient was diagnosed with Spitz nevus. Clinically, most lesions presented as papules or nodules, while a few lesions presented as plaques. Histologically, most tumors were exophytic (9/13). More than half of the tumors were amelanotic and the junctional component was mainly composed of melanocytic nests. Kamino bodies were not found. The bases of the tumors were mainly wedge-shaped (5/13) and flat (7/13). Eight tumors displayed mixed cell types, while 5 tumors were composed of only spindle cells. All the tumors showed a plexiform and/or intersecting fascicular growth pattern, and perineural extension was observed in 3 tumors. ALK immunohistochemistry showed diffuse and intense cytoplasmic staining in 13 cases, and 7 of them were detected by FISH to confirm the presence of ALK fusions. All patients were followed up for 7 to 21 months (median=12), with no recurrence or lymph node dissemination. Conclusions: Spitz tumors with ALK fusions have their special histopathologic features.ALK fusions mainly occur in Spitz nevi and atypical Spitz tumors. The follow-up data of the existing literatures and our research indicates that the prognosis of ALK-positive Spitz tumors may be good.

Phosphaturic mesenchymal tumor with an admixture of epithelial and mesenchymal elements in the jaws: clinicopathological and immunohistochemical analysis of 22 cases with literature review

Information on the heterogeneity of phosphaturic mesenchymal tumor, a rare entity associated with tumor-induced osteomalacia, is limited. In this retrospective analysis of 222 phosphaturic mesenchymal tumors, 22 cases exhibited mixed mesenchymal and epithelial elements, which we propose to term “phosphaturic mesenchymal tumor, mixed epithelial, and connective tissue type.” Phosphaturic mesenchymal tumor of the mixed epithelial and connective tissue type showed a distinctive and significant male predominance (male:female = 2.67:1), with most patients diagnosed at <40 years old. Moreover, all tumors were mainly located in the alveolar bone with focal invasion into surrounding soft tissue and oral mucosa, which could be detected preoperatively by oral examination. The mesenchymal component, composed of spindled cells resembling fibroblasts or myofibroblasts arranged in a storiform or fascicular pattern, exhibited a less prominent vasculature and lower cellularity than the typical phosphaturic mesenchymal tumor (mixed connective tissue type). The epithelial component was typically haphazardly and diffusely distributed throughout the tumor, forming small, irregular nests resembling odontogenic epithelial nests. All cases were immunoreactive for fibroblast growth factor-23, somatostatin receptor 2A, and NSE in both components. Mostly also demonstrated positive staining for CD99 (21/22, 96%), CD56 (16/22, 73%), Bcl-2 (21/22, 96%), and D2-40 (19/22, 86%) in one or both components. S100 was positive in both components in one of seven cases. Interestingly, immunoreactivity was typically stronger and more diffuse in the epithelial than in the paired mesenchymal components. The mesenchymal component was also diffusely positive for CD68 (17/17, 100%) and showed variable focal staining for SMA (15/22, 68%) and CD34 (9/19, 47 %). These results indicate that phosphaturic mesenchymal tumor of the mixed epithelial and connective tissue type has distinctive clinicopathological characteristics and a polyimmunophenotypic profile.

Mediastinal follicular dendritic cell sarcoma: a rare, potentially under-recognized, and often misdiagnosed disease

BackgroundMediastinal follicular dendritic cell sarcoma (FDCS) is extremely rare. Due to potential under-recognization of this disease, it happens to be misdiagnosed, especially on core needle biopsy. We report 3 cases of mediastinal FDCS and provide a literature review to improve better understanding of the tumor and to reduce misdiagnosis.MethodsThree cases of mediastinal FDCS in our clinic practice were studied, including their core needle biopsy and resected specimens, and those cases reported previously in English literature were retrieved and analyzed.ResultsThe core needle biopsy of case 1 showed a tumor reminiscent of classical Hodgkin’s lymphoma (CHL), while the resected mass was finally diagnosed with FDCS combined with hyaline-vascular Castleman’s disease. Both the biopsy and resected tissue of case 2 were constitutive of the clear epithelioid cells with marked atypia. In both cases, definitive diagnoses were not made on core needle biopsy. In case 3, there were some areas morphologically similar to CHL, and some areas contained ovoid to spindle-shaped tumor cells with fascicular pattern. The analysis of 43 cases of mediastinal FDCS showed the age of patients were from 16 to 76 years old, the male to female ratio was 1.5:1, the maximal tumor diameters were 3–17 cm. 18 cases were underwent preoperative biopsy, whereas 15 (83.3%) of which were misdiagnosed initially, often as lymphoma. 32 patients had available follow-up data, the rates of recurrence, metastasis, and mortality were 12.5, 18.8 and 28.1%, respectively. Current limited data suggested no statistical differences between adverse prognosis and gender, age, tumor size, necrosis, or different therapeutics, respectively.ConclusionsMediastinal FDCS is a rare malignancy that has yet not been fully understood and been often misdiagnosed, particularly when making a diagnosis on core needle biopsy. Increased awareness of this enigmatic tumor is crucial to avoid diagnostic pitfalls.

Mucosal Schwann cell hamartomas do occur the gastric mucosa \u2013 report of two cases mimicking fundic gland polyps

Mucosal Schwann cell hamartomas (MSCHs) are recently characterized benign spindle cell lesions of the colon and rectum. There is only one report of MSCHs in the stomach (antrum). Herein, we present the first reports of MSCHs occurring in the fundic mucosa as lesions that endoscopically mimicked a typical fundic gland polyp. Case 1. A 56-year-old woman sought medical attention due to epigastric pain. A small polypoid lesion in the fundic mucosa was removed with an endoscopic impression of a fundic gland polyp. Case 2. A 66-year-old man sought medical attention due to epigastric pain. The patient underwent antral and corporal biopsies that showed mild non-active gastritis without Helicobacter pylori infection. Small polypoid lesions in the fundic mucosa were seen; one was removed with an endoscopic impression of the fundic gland polyp. At the microscope, both lesions were entirely intramucosal, ill-defined spindle cell aggregations, suggesting a fascicular growth pattern. Both lesions were strongly and diffusely positive for S100. Awareness of this lesion is relevant to avoid the diagnosis of other benign spindle cell lesions that are associated with familial syndromes.

A case of a malignant peripheral nerve sheath tumor in a guinea pig

Here, we describe the clinical and histopathological characteristics of a malignant peripheral nerve sheath tumor (MPNST) extending from the dorsal subcutis to the periphery of the spine in a female guinea pig aged 3 years 7 months. The patient presented with pleural and blood-like pericardial effusion and died. The tumor had invaded the spine and the surrounding muscles and had grown in hypercellular and hypocellular arrangements of round, broad-spindle, and elongated-spindle cells. We observed a fascicular growth pattern, nuclear palisading, and perivascular accumulations of cells that responded positively to anti-S100, sox10, and CD56 antibodies. This is the first report of a MPSNT in a guinea pig.

Desmoid-Type Fibromatosis of the Head and Neck Region in A Pediatric Patient: A Case Report

Desmoid-type fibromatosis (desmoid tumor) is a rare and benign locally fibroblastic lesion with aggressive and infiltrative behavior, without distant metastasis. We report the case of a 2-year-old girl, who presented with a 3-month history of swelling of the jaw. Clinical examination revealed a mild diffuse extraoral swelling in the right lower jaw, extending superiorly from the angle of the mouth to the lower border of the mandible. Magnetic resonance imaging showed a soft tissue mass and a mild rupture of the mandibular cortical bone. Incisional biopsy was performed, and microscopic examination revealed uniform and dense cellular proliferation of spindle cells arranged in fascicular patterns. Nuclear beta-catenin expression was detected by using immunohistochemistry. The final diagnosis was desmoid-type fibromatosis. Surgery with negative surgical margins is the most successful treatment modality for this tumor. The literature shows a high recurrence rate for desmoid-type fibromatosis; consequently, long-term follow-up is mandatory.

Establishment and Characterization of a Novel Human Clear-cell Sarcoma of Soft-tissue Cell Line, RSAR001, Derived from Pleural Effusion of a Patient with Pleural Dissemination.

Clear cell sarcoma (CCS) of soft tissue is exceedingly rare and frequently exhibits aggressive behavior. Toward the goals of improving the aggressive course and poor prognosis of CCS, and establish new therapeutic methods, molecular genetic and biological characterizations of CCS are required. A new human CCS cell line (designated RSAR001) was established from the pleural effusion of a 44-year-old man with multiple lung metastases and pleural dissemination. The cell line and its xenograft were characterized including their morphology, immunohistochemistry, cytogenetic analysis, reverse transcription-polymerase chain reaction, direct sequencing analysis, and fluorescence in situ hybridization analysis. The cell line has been maintained for over 12 months with more than 50 passages. RSAR001 cells exhibited a fascicular or diffuse growth pattern of short spindle- or oval-shaped cells with clear cytoplasm in heterotransplanted tumor, that was similar to the primary tumor. Immunophenotypically, RSAR001 cells in vitro and in vivo exhibited almost the same characteristics as the primary tumor. Cytogenetic analyses revealed a translocation, t(12;22)(q13;q12). Reverse transcription-polymerase chain reaction and direct sequencing analysis detected transcripts of the Ewing sarcoma breakpoint region 1-activating transcription factor 1 (EWSR1-ATF1) type 1 fusion gene. Fluorescence in situ hybridization using a break-apart probe for the EWSR1 gene on 22q12 showed a rearrangement. These findings indicate that the RSAR001 cell line harbors EWSR1-ATF1 type 1 chimeric fusion gene, which is specific to CCS. RSAR001 cells might be useful for investigating biological behaviors and developing new treatments such as molecular-targeting antitumor drugs or immunological drugs for CCS.

Inflammatory Myofibroblastic Tumor in Female Genital Tract.

Inflammatory myofibroblastic tumor is a mesenchymal neoplasm of low malignant potential. It was first described in lung, but is known to occur in many extrapulmonary sites including female genital organs, most commonly the uterus. It has a high recurrence rate and a low risk for metastasis. A more recently described aggressive variant, epithelioid myofibroblastic sarcoma with a predilection for the abdominal cavity of males, has also been recently reported to occur in the ovary. This tumor is composed of spindled and epithelioid myofibroblasts in a variably myxoid stroma and commonly shows a fascicular growth pattern with positive staining for desmin, smooth muscle actin, and CD10, which may mimic a smooth muscle or endometrial stromal neoplasm. In the female genital tract it has the potential for being misdiagnosed as a leiomyoma, endometrial stromal tumor, or as a myxoid leiomyosarcoma, resulting in undertreatment or overtreatment. It harbors rearrangements in the ALK gene, resulting in abnormal expression of ALK protein. Immunostaining for ALK is a helpful diagnostic tool. To provide a brief review of clinical, histologic, immunohistochemical, and molecular features of inflammatory myofibroblastic tumor with emphasis on possible diagnostic pitfalls in the female genital tract. Review of pertinent literature on inflammatory myofibroblastic tumor occurring in the female genital tract and personal experience of the authors. Inflammatory myofibroblastic tumor in the female genital tract can mimic other more common benign and malignant tumors like leiomyoma, leiomyosarcoma, and endometrial stromal sarcoma. Familiarity with clinical and histologic features and use of ALK immunostaining can be critical for correct diagnosis.

A case of malignant solitary fibrous tumor of the prostatic urethra.

A 68-year-old male with dementia presented with gross hematuria. On plain CT, a mass was found at the base of the prostate with intravesical protrusion. On MRI, the mass was well-circumscribed and showed slight hyperintensity compared to the skeletal muscle on T 1 weighted imaging and high intensity on T 2 weighted imaging. On dynamic study, the tumor showed mild enhancement in the early phase and increased enhancement in the delayed phase, and the mass appeared continuous with the prostatic urethra. On follow-up MRI at approximately 10 months, the mass had increased in size. Pathologically, the tumor was located in the muscularis of the prostatic urethra and consisted of spindle cells with fascicular and storiform patterns of growth, and exhibited strong diffuse expression of CD34. The tumor was hypercellular, and a significant number of mitoses were observed. Therefore, this tumor was diagnosed as malignant solitary fibrous tumor (SFT) of the prostatic urethra.

F32. Very-high vs high resolution sonography in the evaluation of the posterior tibial and sural nerve: Preliminary data in healthy subjects

High resolution ultrasonography (HRUS) of peripheral nerves is an emerging tool in investigating peripheral nerves, complementary to electrodiagnostic tests, and it is commonly performed using a linear array transducer with upper frequencies between 12 and 19 MHz. Since 2016 a very-high-resolution US (VHRUS) device is available for clinical use (Vevo-MD) that incorporates transducers with upper frequencies of 48 MHz (pixel resolution 50 μm, depth 2.3 cm) and 70 MHz (pixel resolution 30 μm, depth 1 cm). Our aim was to investigate the potential role of VHRUS in the assessment of the posterior tibial nerve (PTN) and sural nerve (SN) healthy echographic features being both commonly involved in peripheral neuropathies. We studied these nerves (at the ankle) in 10 healthy subjects, comparing images obtained with VHRUS to those usually obtained with a 19 MHz HRUS. In particular, we compared 19 vs 48 MHz for PNT and 19 vs 70 MHz for SN. We measured nerves’ areas, perimeters and fascicular pattern obtained from the images acquired with both devices by using dedicated offline post-processing tools, and we compared the respective values. Our data show significant agreement in the measurements of area and perimeter obtained with both devices. However, using VHRUS we experienced a much higher degree of confidence in visualizing both nerves and their internal structure thanks to its superior spatial resolution. We also noticed that scanning depth was always sufficient for this diagnostic task. VHRUS shows promising advantages compared with HRUS although further studies are needed to validate its use also in subjects with well-established peripheral neuropathies.