Cellular Pleomorphism Research Articles

Characterization of different tissue changes in normal, betel chewers, potentially malignant lesions, conditions and oral squamous cell carcinoma using reflectance confocal microscopy: Correlation with routine histopathology

The goal of this study was to characterize the features of normal mucosa, mucosa in betel chewers and smokers, potentially malignant lesions and squamous cell carcinoma of oral mucosa using reflectance confocal microscopy. Oral cavity biopsies were acquired from 25 patients from College of Dental Surgery, Saveetha University who underwent screening for suspected lesions of Oral precancer and Oral cancer along with normal patients who underwent impaction. Biopsies were acquired from the clinically suspicious area and immediately placed in Dulbecco modified eagles growth medium (DMEM). Reflectance confocal images were obtained at multiple image plane depths from biopsies within 6h of excision. After imaging, biopsies were fixed in 10% formalin and submitted for routine histopathological examination by an experienced oral and maxillofacial pathologist. Reflectance confocal images were compared with histological images from the same sample to determine the tissue features which contribute to early cellular changes, image contrast and early diagnosis. The confocal images were obtained to a depth of up to 150 microns on intact biopsy specimens and subsequent 3-dimensional images, keratin thickness measurements, cell measurements, cell density analysis and graphical representations were performed using Leica image analysis software. In normal mucosa keratin deposition were seen as alternating dark and bright stacks and in different cell layers the nuclei were seen as disks of varying intensities. In pre-cancerous lesions the keratin thickness and cell nuclear density were found to be increased when compared to normal controls. In OSMF cases confocal images of fibrosis show scattering from individual fibres as hyperdense areas. Oral squamous cell carcinoma cases demonstrated extensive variations in cell size, nuclear size and nuclear morphology. At cellular level, dysplastic features like increased nuclear density, increased nuclear cytoplasmic ratio, nuclear and cellular pleomorphism with loss of cohesiveness were identified in all five cases. Our results support the potential of reflectance confocal microscopy to play a significant role in clinical evaluations of oral lesions, early diagnosis of potentially malignant and malignant oral lesions and real time identification of tumour margins.

Primary Leiomyosarcoma of the Kidney: A Clinicopathologic Study of 27 Cases

Primary leiomyosarcoma of the kidney is a rare entity that has not been well characterized. We retrieved 27 cases of primary renal leiomyosarcomas diagnosed at 3 institutions between 1986 and 2009. Mean patient age at diagnosis was 58.5 years (range 22 to 85), and 59% were female. Mean tumor size was 13.4 cm (range 4 to 26), and 59% of the tumors were identified in the right kidney. Detailed histologic examination was possible for 24 of the cases. Average mitotic count per 10 high-power fields was 11.1 (range 0 to 50), and the average extent of necrosis was 21% (range 0 to 60). Cellular pleomorphism was classified as either focal (n = 13) or extensive (n = 11) and graded as mild (n = 3), moderate (n = 7) or severe (n = 14). Tumors were either grade 2 (n = 12) or grade 3 (n = 12) using the French Federation of Cancer Centers System. Direct extension beyond the kidney capsule was identified in 55% of the cases, and lymphovascular invasion was identified in 26%. Clinical follow-up information was available for 20 of the cases, and patients were followed for an average of 2.8 years (range 0.25 to 9). Distant metastases were identified in 90% of the patients, and 75% eventually died from their tumor's burden. In conclusion, primary renal leiomyosarcomas have a grim prognosis regardless of the underlying histology.

Dural based primary osteosarcoma in right fronto-temporal region:Case report with review of literature

We report a case of primary dural based osteosarcoma in the right fronto-temporal convexity in a 43-year-old female who presented with a short history of seizure and headache. Radiologic evaluation revealed a well defined brightly enhancing extra-axial lesion in the right fronto-temporal region with a dural tail around the sylvian fissure. The overlying bone was uninvolved. Paraffin section of the tumor showed plump cells with moderate nuclear and cellular pleomorphism with eosinophilic extracellular material (osteiod) between the cells. At a few places, lace like osteiod was seen encasing individual cells signifying osteiod being formed by tumor cells. Immunohistochemistry for EMA was focally positive and negative for S-100 protein and GFAP. A final histopathological diagnosis of dural based primary osteosarcoma of the right fronto-temporal region was rendered. To the best of our knowledge this will be the eighth such case in literature.

Successful type-oriented endoscopic resection for gastric carcinoid tumors: A case report

The standard treatment in Japan for gastric carcinoid has been gastrectomy with lymphadenectomy. This report describes the possibility of endoscopic treatment as an appropriate option for gastric carcinoid fulfilling certain conditions. A 46 year old woman underwent endoscopic mucosal resection for two 3 mm gastric carcinoids. The patient had hypergastrinemia with pernicious anemia and type A chronic atrophic gastritis, suggesting that the tumors were type I in Rindi's classification. Both tumors were located in the mucosal layer with no cellular polymorphism and were chromogranin A positive. Neither tumor recurrence in the stomach nor distant metastases have been documented during the 5 years of follow-up. Although many type I gastric carcinoids may be clinically indolent, reports on successful endoscopic treatment for this carcinoid have been scanty in the literature in Japan, presumably because of the hitherto surgical treatment stance for the disease. This report discusses how the size, number, depth and histological grading of the type I gastric carcinoid could allow the correct identification of a benign or malignant propensity of an individual tumor and how endoscopic resection could be a treatment of choice when these factors render it feasible. This stance could also obviate unnecessary surgical resection for more benign tumors.

Primary spinal melanoma of the cervical leptomeninges: Report of a case with brief review of literature

Central nervous system primary malignant melanoma accounts for approximately 1% of all melanomas. Primary spinal melanomas are even more unusual. We report a patient with primary spinal melanoma of the cervical leptomeninges. The histology of the tumor showed tumor cells arranged in sheets, ill-defined fascicles and nests and displayed a moderate grade of cellular and nuclear pleomorphism and mitoses with abundant pigment in the cytoplasm. The tumor cells were immunoreactive for HMB-45, and for S-100.

Anaplastic Pleomorphic Xanthoastrocytoma With a Component of Anaplastic Astrocytoma Presenting as Skull Base Tumor Followed by Downward Extracranial Extension -Case Report-

A 16-year-old female, with unremarkable medical and family history, presented with a huge dural-based mass in the right frontotemporal fossae, manifesting as headache. The patient underwent subtotal tumor resection. Intraoperative findings revealed focal erosion in the temporal fossa dura mater and skull adjacent to the lesion. Most of the tumor was located extraaxially, but a part of the tumor had invaded the temporal lobe, and had tightly adhered to the middle cerebral artery and its perforating vessels. Histological examination revealed cellular pleomorphism with mitotic activity, focal necrosis, but lacking endothelial proliferation, consistent with anaplastic pleomorphic xanthoastrocytoma (PXA) with component of anaplastic astrocytoma. Postoperatively, the patient underwent local irradiation and temozolomide administration, but the tumor relapsed 13 months later. Second tumor resection was performed followed by gamma knife radiosurgery, but the residual tumor progressively grew, extending into the contralateral hemisphere, and formed an enormous mass in the left frontal lobe at 17 months. Magnetic resonance imaging performed at 18 months revealed extracranial infiltration of the frontal tumor, through the cribriform plate, with enormous extension into the paranasal sinuses, nasal cavity, and orbit during the next month. The patient died at 20 months after the initial surgery. PXA with anaplastic appearance may have a component of anaplastic astrocytoma with more aggressive behavior.

Solitary fibrous tumour of the central nervous system: pathological study of eight cases and review of the literature

Solitary fibrous tumours (SFT) of the central nervous system are rare neoplasms that usually present as dura-based masses and clinically resemble meningiomas. Histologically, they can be similar to haemangiopericytoma or fibrous meningioma. We present herewith a pathological study of eight patients with SFT and compare our results with the published data. All tumours diagnosed as SFT over a period of 15 years were retrieved from the files of La Rabta Hospital Department of Pathology, Tunisia. Routine histological sections were prepared from formalin-fixed, paraffin-embedded specimens. Immunohistochemical analysis was performed using antibodies raised against vimentin, CD34, CD99, Bcl-2 and MIB-1. The SFT group consisted of four males and four females with a mean age of 44 years. The tumours were supratentorial in six cases, tentorial in one case and located in the lateral right ventricle in the last case. All patients underwent surgery as initial treatment. Histologically, SFT were similar to their soft tissue counterparts. Two cases demonstrated increased cellularity, marked nuclear hyperchromasia and marked cellular pleomorphism. Only the later two cases recurred after 6 months of follow-up. Little is known about the biological behaviour of SFT, although most seem amenable to total resection.

Cancer papillaire sur goitre dyshormonogénétique

Introduction Dyshormonogenetic goiter is a genetically determined thyroid hyperplasia due to an enzyme defect in thyroid-hormone synthesis. Malignant transformation is one of the most serious complications, rarely reported in the literature. Observation We report a new case of a 13-year-old boy with goitrous hypothyroidism who consulted for a voluminous goiter. Total thyroidectomy was performed. Histopathological examination revealed multiple foci of papillary carcinoma with a lymph node metastasis. Conclusion Dyshormonogenetic goiter is a rare entity, representing one of the causes of congenital hypothyroidism. It is morphologically characterized by architectural and cellular pleomorphism that may mimic thyroid malignancy and cause difficulties in differential diagnosis.

Pathological characteristics of gastrointestinal stromal tumours with PDGFRA mutations

The aim of this study was to identify the characteristics of PDGFRA-mutated gastrointestinal stromal tumours (GISTs) in comparison with KIT-mutated GISTs. A total of 151 GISTs were examined for KIT and PDGFRA mutations, and clinical and histopathological parameters were evaluated and analysed statistically according to mutation status. KIT and PDGFRA mutations were detected in 123 (81.5%) and 15 cases (9.9%), respectively. Clinically, all PDGFRA-mutated GISTs were located in the stomach with no recurrences and tumour-related deaths were noted. Pathological parameters associated with PDGFRA mutations were epithelioid and mixed type, low to moderate cellularity, moderate to severe intratumoural lymphocytic infiltration, prominent myxoid change, frequent rhabdoid cells and multinucleated giant cells, increased cellular pleomorphism, low mitotic count, and lower risk assessment (p < 0.05). Compared with KIT-mutated GISTs, PDGFRA-mutated GISTs had unique histopathological patterns, intermingling of spindle and epithelioid cells, and/or a jigsaw puzzle-like arrangement of epithelioid cells. PDGFRA-mutated GISTs have distinctive histological patterns that are differentiated from KIT-mutated GISTs. The algorithmic approach by a combination of several distinguishing histological and immunohistochemical features between KIT- and PDGFRA-mutated GISTs might be helpful in predicting the mutated gene of each GIST on pathological examination.

Angiofibrolipoma of the spermatic cord

Dear Sir, I am Dr Qing-Li Liu, from the Department of Urology of the First Hospital of Qinhuangdao in Qinhuangdao, Hebei Province, China. I write to present a case report of spermatic cord angiofibrolipoma. Angiofibrolipoma is a histological variant of lipoma, which usually presents as a solitary, subcutaneous, circumscribed lesion in the back, neck or shoulders. Here, we report a case of angiofibrolipoma of the spermatic cord. To our knowledge, such a case has not been previously reported in the literature. A 3-year-old boy presented with a right inguinal mass that had first been noticed 1 month earlier. On physical examination, the mass was located in the right spermatic cord and felt elastic, with no tenderness. The transillumination test was negative. Ultrasonography of the spermatic cord revealed a cystic-solid echo mass lesion, 2.5 cm in diameter, with minimum blood flow. Under general anaesthesia, a 3-cm inguinal oblique incision was made and the spermatic cord was isolated and occluded with a noncrushing clamp at the level of the internal ring. A tumour was found under the internal spermatic fascia; the tumour had a well-circumscribed boundary and was not adjacent to the right testicle and epididymis. The spermatic vessels and vas deferens were identified posterior to the mass. A 0.2-cm-thick pseudo-capsule surrounded the entire tumour. After the spermatic vessels and vas deferens were securely protected, the tumour was completely removed. Macroscopic examination revealed that the cut surface of the tumour was a multilocular cyst filled with blood, and there were no necrotic or cystic changes. The pathological examination revealed mature adipocytes, blood vessels and dense collagenous tissue (Figure 1), without the evidence of mitosis or cellular pleomorphism. These findings were consistent with angiofibrolipoma. At 6-month follow-up, there was no evidence of recurrence and the right testicle size was normal. Figure 1 A histological study (H&E stain) showed the three characteristic findings of angiofibrolipomas: mature adipocytes, blood vessels and dense collagenous tissue. (A): Low-power and (B): high-power views. Scale bar = 125 μm Tumours of the spermatic cord are rare. Overall, 30% of such tumours are malignant; and the rest are benign. Lipoma is the most common benign lesion; among the others are leiomyomas, dermoid cysts, epidermoid cysts and lymphangiomas 1. The conventional lipoma is a collection of mature adipocytes arising from subcutaneous tissues of the trunk, neck and proximal extremities 2. Histological variants of lipomas include fibrolipomas, angiolipomas, angiofibrolipomas, angiomyolipomas and infiltrating angiolipomas. These lesions are categorized according to their content of fat, muscle, blood vessel and connective tissue. The growths are not encapsulated but are histologically distinct from surrounding tissues. They have low-to-moderate cellularity and are not clinically aggressive 3, 4. Angiofibrolipomas are a mixture of mature adipocytes, vascular tissue and collagenous connective tissue. To our knowledge, the present case study is the first report of a spermatic cord angiofibrolipoma. The patient presented with an elastic inguinal mass on physical examination, and the diagnosis required histopathological assessment. Perhaps a preoperative incisional biopsy of the lesion could have confirmed the diagnosis before definitive resection. However, as with any lipoma, complete surgical excision and histopathological confirmation of margins are adequate for both diagnosis and treatment. During the operation, we found a fibrous pseudo-capsule, which was formed through a desmoplastic reaction 5. The pseudo-capsule was helpful in the tumour resection and in protecting the spermatic vessels and vas deferens from damage. In such cases, surgical excision, histological examination and long-term follow-up for recurrence are recommended.

A rare case of atypical cellular neurothekeoma in a 68‐year‐old woman

Cellular neurothekeoma is a benign dermal lesion of uncertain differentiation. The atypical variant of cellular neurothekeoma, characterized by features such as large size, deep penetration, diffusely infiltrative borders, vascular invasion, high mitotic rate and marked cytologic pleomorphism, has been very rarely reported in the literature. We present the clinical, histopathological and immunohistochemical profile of a new case of atypical cellular neurothekeoma in a 68-year-old female patient who was diagnosed with ductal breast carcinoma in situ before. An erythematous painless papule arose in her right breast, and tentative clinical diagnosis was orientated toward skin metastasis of breast cancer or fibroma. Upon histological examination, the lesion showed the histological and immunohistochemical features of atypical variant of cellular neurothekeoma with high mitotic rate, marked cellular pleomorphism and penetration into subcutaneous fat. A further unusual feature in our patient was her age, because she is the oldest patient reported in the literature with diagnosis of atypical cellular neurothekeoma so far. Prognosis remains uncertain because only few cases of atypical cellular neurothekeoma have been reported in the literature, with a very limited follow-up time. Our report contributes to a better characterization of the clinical and morphologic features of atypical cellular neurothekeoma.

Symplastic glomus tumor – a rare but distinct benign histological variant with analogy to other ‘ancient’ benign skin neoplasms

A 78-year-old woman presented with a nail deformity of the index finger of the left hand associated with paroxysmal pain upon cold exposure. Histologically, a well-circumscribed tumor of 3 mm diameter was found in the dermis. The neoplastic cells in some areas were of pronouncedly variable size and cytomorphology, mostly epithelioid in shape, with eosinophilic cytoplasm and indistinctly defined cell borders. Pronounced nuclear pleomorphism and atypia were striking features, but no mitotic figures were noted. Multinuclear cells were present as were numerous small-to-medium vessels throughout the tumor. The tumor stroma showed myxoid areas. Immunohistochemistry showed cytoplasmic and membranous expression of smooth muscle actin and vimentin. The histological features and immunoprofile were consistent with the diagnosis of symplastic glomus tumor, a rare histological variant, which has been defined as a glomus tumor exhibiting marked nuclear atypia, in the absence of any other criteria for malignancy. The biological behavior of the tumor is benign. It is essential to differentiate this entity from malignant glomus tumor, which has metastatic potential. Even prominent cellular atypia and nuclear pleomorphism in a glomus tumor as in our case is not a marker of malignancy in the absence of additional criteria.

Trichilemmal Cyst With Carcinoma In Situ Within an Atypical Fibroxanthoma

A 91-year-old lady presented with an 8-month history of a slow growing keratotic nodule on the forehead, which was excised. Histological examination showed a well-defined lesion with marked cellular pleomorphism. Numerous mitoses were present. The cells stained positively with CD10 and CD68 and weakly with smooth muscle actin. However, the tumor was negative for cytokeratins (AE1/AE3), epithelial membrane antigen (EMA), S100, Melan A, HMB45, leukocyte common antigen (LCA), desmin, and CD31. Therefore, the lesion was designated as atypical fibroxanthoma (AFX) by exclusion. Within the AFX, there was also a cyst lined by squamous epithelium showing pilar keratinization. The epithelium showed full-thickness dysplasia with increased mitotic activity and was stained positively with AE1/AE3, thus supporting our view of carcinoma in situ within the wall of the cyst. To the best of our knowledge, this article describes the first case of trichilemmal cyst with carcinoma in situ arising within an AFX.

Inhibition of vinyl carbamate-induced pulmonary adenocarcinoma by indole-3-carbinol and myo-inositol in A/J mice

In previous studies, we reported that indole-3-carbinol (I3C) and myo-inositol (MI) inhibit lung adenoma induced by tobacco smoke carcinogens in A/J mice. In this paper, we extended our work and examined the effects of I3C (70 or 30 micromol/g diet) and MI (56 micromol/g diet) against vinyl carbamate (VC)-induced lung adenocarcinoma by administering the agents from 1 week after the second of two injections of VC until termination of the study at week 18. The higher dose of I3C decreased multiplicities of tumors on the surface of the lung (26%, P = 0.0005), carcinoma incidence (38%), multiplicity (67%, P < 0.0001) and size (complete abolition of carcinoma with an area of >1.0 cm(2)) as well as adenoma with cellular pleomorphism (46%, P < 0.0001). The lower dose of I3C was less effective. MI decreased multiplicities of pulmonary surface tumors (20%, P = 0.0005), adenoma with cellular pleomorphism (40%, P < 0.0001) and lung adenoma (52%, P < 0.0001) and the proportion of the biggest carcinoma (carcinoma with an area of >1.0 cm(2), P < 0.05). Immunoblot analyses of lung tissues for potential target identification showed that I3C (70 micromol/g diet) inhibits IkappaBalpha degradation, nuclear factor-kappaB activation, expression of cyclooxygenase-2, phospho-Akt and fatty acid synthase (FAS) and activates caspase-3 and poly ADP ribose polymerase cleavage. The effect of MI was limited to inhibition of phospho-Akt and FAS expression. Our data show that I3C and MI inhibit lung carcinoma and provide a basis for future evaluation of these compounds in clinical trials as chemopreventive agents for current and former smokers.

Endoscopic submucosal dissection for rectal carcinoid tumors

Endoscopic submucosal dissection (ESD) has an advantage over endoscopic mucosa resection (EMR) by enabling removal of gastrointestinal neoplasms en bloc. The ESD procedure is the treatment of choice for rectal carcinoids that have classic histologic architecture with minimal cellular pleomorphism and sparse mitoses, but it has not been applied for such tumors. The ESD procedure was performed for patients with colorectal tumors that fulfilled the inclusion criteria specifying tumor with a diameter of 10 mm or less, no muscular layer invasion, and no metastases to the lymph nodes or distal organs. The ESD procedure was performed for patients with rectal carcinoids but no node or distal metastasis. This study enrolled 20 rectal carcinoid tumors from 20 consecutive patients. The mean tumor size was 7.6 mm (range, 3-16 mm). En bloc removal was achieved for all the tumors, and the complete resection (en bloc with tumor-free lateral/basal margins) rate was 90% (18/20). The two cases in which the margins were not evaluable due to burn effects still are free of recurrence and metastasis at this writing. Perforation was seen in one case, which was managed nonsurgically. Precise histolopathogic assessment of the specimens resected en bloc by ESD may reduce tumor recurrence and metastasis after ESD. As the treatment of choice for small rectal carcinoids, ESD is associated with nominal risks of metastatic disease.

Solitary fibrous tumors of the pleura presenting satellite tumors

A 29-year-old man presented with a mass in the left lower lung field on a chest radiograph obtained during a medical checkup. Computed tomography revealed a tumor adjacent to the diaphragm. A sessile tumor measuring 10.5 x 8.5 x 4.5 cm arising from the parietal pleura was resected. The tumor was accompanied by several little tumors on the nearby diaphragm. Pathologically, the major tumor consisted of typical spindle-shaped cells with myxoid degeneration. There was no increased cellularity, cellular pleomorphism, or a high mitotic count. In immunohistochemical studies, the spindle cells showed positive staining for CD34 and were negative for bcl-2. The smaller tumors also consisted of myxoid degeneration. We diagnosed benign solitary fibrous tumor of the pleura with satellite tumors. We must be aware of the possibility of satellite tumors when we treat patients with a benign solitary fibrous tumor.

Cytomorphological changes after ultrasound‐guided percutaneous ethanol injection in benign thyroid nodules

To characterize the cytomorphological changes after percutaneous ethanol injection (PEI) in benign thyroid nodules, we compared the cytological features of fine needle aspiration cytology (FNAC) samples before and after PEI. Fifty-five cases diagnosed with adenomatous goitre (group 1, 35 cases) or cystic changes only (group 2, 20 cases) were included. In all cases, FNACs were performed by the pathologists before and after PEI. PEI was performed in all cases by a diagnostic radiologist according to the ultrasound guidelines. The following cytological features were evaluated by two pathologists: cellularity of follicular epithelial cells, background, cellular pleomorphism, nuclear/cytoplasmic (N/C) ratio, chromatin pattern, presence of nucleoli, macrophages, multinucleated giant cells, and mitosis. In group 1, 19 cases (54%) showed changes in cellularity after PEI, with reduced cellularity in 13 cases (37%) and increased cellularity in six cases (17%). No necrotic background was observed before PEI; however, 14 cases (40%) developed necrotic background after PEI (P < 0.0001). Multinucleated giant cells were observed in 18 cases (51%) after PEI, which is in contrast to four cases (11%) before PEI (P = 0.001). In group 2, necrotic background was seen in 11 cases (55%, P < 0.0001) and multinucleated giant cells were observed in four cases (20%) after PEI. Necrotic background and presence of multinucleated giant cells are indicative of tissue damage caused by PEI in the FNAC specimens of benign thyroid nodules. In contrast to other modalities including chemotherapy or radiation treatment for malignant tumour, no unusual cytological change is observed after PEI.

Anaplastic large cell lymphoma: one or more entities among T‐cell lymphoma?

Anaplastic large cell lymphoma (ALCL) is a subtype of peripheral T-cell lymphoma (PTCL) first described in 1985 as a lymphoid malignancy characterized by marked cellular pleomorphism, propensity to grow cohesively, tendency to invade lymph node sinuses and diffuse expression of CD30 1. The discovery of the t(2;5), involving the anaplastic lymphoma kinase (ALK) gene on chromosome 2 and the nucleophosmin (NPM) gene on chromosome 5 in the majority of systemic ALCL, has soon pointed out that ALCL is a clinically and biologically heterogeneous disease. While ALK-positive (ALK+) ALCL is usually characterized by onset in children and young adults and better prognosis, epidemiology, poor outcome and possibly genetic defects of ALK-negative (ALK-) ALCL suggest that this neoplasms should be considered an independent pathological entity. The aim of this review is to illustrate clinical features, histology, immunophenotype, genetics and biology of ALCL and discuss possible relationship(s) among different T-non-Hodgkin lymphoma (T-NHL).

Plantar Melanoma That Mimics Melanocytic Nevi: A Report of 4 Cases With Lymph Node Metastases and With Review of Positive and Negative Controls

We report 4 cases of melanoma localized on the sole with some striking histological similarities to the compound nevi. One case showed inguinal lymph node metastases after a diagnosis of compound nevus made 5 years earlier. The other 3 cases were sent to us in consultation as suspected plantar lesions; a diagnosis of melanoma mimicking compound nevus was proposed: the sentinel lymph node technique was accordingly performed and resulted positive. These 4 index cases were compared with 26 cases of ordinary plantar melanoma and with 117 cases of benign compound plantar nevi. Histologically, the similarity of areas of these 4 cases of plantar melanoma to compound plantar nevi (namely Miescher, Clark, or acral lentiginous nevus) is so close that it may prove misleading in the diagnostic pathway. In such cases, an erroneous diagnosis of benign lesion may be made. The correct diagnosis of melanoma can, however, be done by combining the clinical and pathological findings. In fact, this deceptive form of melanoma mimicking a compound nevus is characterized by patients' advanced age (>45 years), large lateral diameters (>10 mm), and significant depth of the lesion (>1 mm). In our 4 cases, such features were combined with one or more of the following histological clues: lentiginous (ie, continuous) proliferation of enlarged and hyperchromatic melanocytes aligned in single units at the dermoepidermal junction; extensive eccrine duct melanocytic infiltration; dermal melanocytes with slight nuclear enlargement, nuclear membrane thickening and folding, and conspicuous central nucleoli; and cellular pleomorphism of the epidermal and dermal component. Moreover, mitotic figures were an inconstant but decisive indication of malignancy. In conclusion, a small group of plantar melanoma has striking similarities with compound nevi. Only the correlation of clinical data (old age of the patient and large size of the lesion) with subtle architectural and cytological alterations (depth of the lesion, lentiginous melanocytic epidermal and eccrine proliferation, and cellular alteration and mitoses) allows a correct diagnosis.

Well-differentiated papillary mesothelioma of the tunica vaginalis: A case report with aspirate cytologic, immunohistochemical, and ultrastructural studies

A case of a well-differentiated papillary mesothelioma of the tunica vaginalis testis in a 70-year-old man, who presented with a 1-month history of scrotal swelling with hydrocele, is described. Fine needle aspiration cytology of the hydrocele demonstrated a papillary cluster of uniform round cells with minimal atypia, reminiscent of mesothelial cells. Macroscopically, the lesion was characterized by a solitary, well-circumscribed papillary soft tumor measuring 1.2×1.2×1.0 cm 3. Histologically, the tumor exhibited papillary or tubulopapillary proliferation of predominantly bland cuboidal cells. No cellular pleomorphism, mitotic figures, necrosis, or stromal invasion was noted. Immunohistochemically, the tumor was positive for CAM5.2, epithelial membrane antigen, vimentin, calretinin, and D2-40, but negative for carcinoembryonic antigen. Ki-67 index was less than 1%. Ultrastructurally, the tumor cells showed numerous microvilli, mitochondria, rough endoplasmic reticulum, microfilaments, and desmosomes. The patient is alive with no evidence of disease at 18 months after right radical orchiectomy. Ki67 may be potentially a good maker for differentiating low-grade from high-grade mesothelioma.