Malignant melanoma with a rhabdoid phenotype: histologic, immunohistochemical, and ultrastructural study of a case and review of the literature

Malignant melanoma is known to display tremendous histologic diversity. One rare variant is the rhabdoid phenotype, so called because of the appearance of cells resembling rhabdomyoblasts seen in malignant rhabdoid tumors of the kidney. We present the histologic, immunohistochemical, and ultrastructural features of a malignant melanoma composed entirely of rhabdoid cells. A 62-year-old man presented with a 6.5-cm lung mass. Although presumed to be a metastatic lesion, extensive workup failed to reveal a primary tumor site. Histologic sections showed a mass composed entirely of polygonal neoplastic cells with prominent nucleoli and large hyaline cytoplasmic inclusions. The tumor cells were strongly immunoreactive with S100 protein, vimentin, and CD56, and were focally reactive with Mart-1. Tumor cells were negative for Melan-A, tyrosinase, HMB-45, AE1/AE3, cytokeratin (CK) 7, CK8/ 18, CK20, CK903, CAM 5.2, epithelial membrane antigen, smooth muscle actin, desmin, leukocyte common antigen, Bcl-2, CD3, CD20, CD30, CD138, kappa and lambda light chains, CD68, CD34, factor VIII, synaptophysin, and glial fibrillary acidic protein. Electron microscopy showed cytoplasmic whorls of intermediate filaments containing entrapped rough endoplasmic reticulum, mitochondria, and lipid. Recognition of this rare variant of malignant melanoma is important in the evaluation of tumors with rhabdoid morphology.     

Epithelioid smooth muscle tumors of the uterus do not express CD1a: a potential immunohistochemical adjunct in their distinction from uterine perivascular epithelioid cell tumors

Uterine epithelioid smooth muscle tumors and uterine perivascular epithelioid cell tumors (PEComas) are known to display such a substantial overlap in morphologic and immunophenotypic characteristics that the existence of the latter as a distinct clinicopathologic entity at this location has been called into question. Recent research suggests that the constituent entities of the PEComa family at all anatomical locations, including lymphangioleiomyomatosis of the uterus, uniformly display immunoreactivity for CD1a. The purpose of this study is to determine the proportion of uterine epithelioid smooth muscle tumors that may similarly be CD1a-positive. Representative sections from 18 archived epithelioid smooth muscle tumors of the uterine corpus (6 epithelioid leiomyosarcomas and 12 epithelioid leiomyomas), diagnosed and classified as such based on World Health Organization criteria, were subjected to immunohistochemical stains for CD1a and HMB-45. The epithelioid component of the tissue sections evaluated ranged from 10% to 100% (mean, 70%). Two cases were composed predominantly of cells with overtly clear cytoplasm. All cases were entirely negative for CD1a. Of 18 cases, 1 (5.5%) (an epithelioid leiomyosarcoma) displayed immunoreactivity for HMB-45 in scattered lesional cells that constituted approximately 5% of the overall tumoral volume for the case. All others were HMB-45-negative. Given their rarity, future studies are required to confirm that all PEComas of the uterus are indeed uniformly positive for CD1a. However, if the latter staining pattern is confirmed, our findings herein suggest that CD1a may be a useful immunohistochemical adjunct in distinguishing uterine epithelioid smooth muscle tumors from uterine PEComas.     

Pulmonary gangliocytic paraganglioma: a case report and review of the literature

Gangliocytic paraganglioma (GP) is a rare histologic type of neuroendocrine tumors. We report a case of pulmonary GP in a 29-year-old male presenting with an asymptomatic endobronchial nodule. Grossly, the tumor showed a 4.0x3.8x3.5 cm well-defined nodule with yellowish cut surface. Microscopically, the tumor was composed of three distinct cellular types: epithelioid cells, ganglion-like cells and spindle cells. Meanwhile, transitional cells, having morphologic features between ganglion-like and epithelioid cells, were also presented. The epithelioid cells arranged in various morphologic architectures, including Zellballen, papillary, cystic and microcystic pattern. The epithelioid cells were positive for AE1/AE3, CAM 5.2, chromogranin A and synaptophysin. Ganglion-like cells showed immunoreactivity for chromogranin A and synaptophysin. A few ganglion-like cells were also positive for AE1/AE3 and/or CAM 5.2. The spindle cells were positive for S-100 protein and neurofilament. The transitional cells showed a similar immunohistochemical profile to the epithelioid cells. The authors believe stem cell theory is a reasonable explanation for the origin of GP. GP probably originate from some kind of mucosa associated stem cell which can differentiate into diverse cellular lineages.     

Adenomatoid tumour of the liver

An unusual primary adenomatoid tumour arising in the normal liver is described. Hepatectomy was performed, and the patient is alive and free of disease 1 year postsurgery. Grossly, the tumour showed a haemorrhagic cut surface with numerous microcystic structures. Histological examination revealed cystic or angiomatoid spaces of various sizes lined by cuboidal, low-columnar, or flattened epithelioid cells with vacuolated cytoplasm and round to oval nuclei. The epithelioid cells were entirely supported by proliferated capillaries and arteries together with collagenous stroma. Immunohistochemical studies showed that the epithelioid cells were strongly positive for a broad spectrum of cytokeratins (AE1/AE3, CAM5.2, epithelial membrane antigen and cytokeratin 7) and mesothelial markers (calretinin, Wilms' tumour 1 and D2-40). These cells were negative for Hep par-1, carcinoembryonic antigen, neural cell adhesion molecule, CD34, CD31 and HMB45. Atypically, abundant capillaries were observed; however, the cystic proliferation of epithelioid cells with vacuoles and immunohistochemical profile of the epithelioid element were consistent with hepatic adenomatoid tumour.     

Adult ocular medulloepithelioma diagnosed by transscleral fine needle aspiration: A case report

Ocular medulloepithelioma (ME) is a rare congenital tumor which occurs usually during childhood but is also reported in adults. They have seen an intraocular tumor in an 89 years‐old female with a history of small cell lung carcinoma. Transscleral fine needle aspiration was performed. Aspirates were rich and composed of two distinctive populations of cells. The first consisted of epithelioid large cohesive cells with rare rosettes. Nuclei were oval and chromatin was delicate with small nucleoli. The second population consisted of smaller and dispersed cells with regular nuclei and dusty chromatin. Immunohistochemistry performed on paraffin‐embedded cell block sections showed that the larger cells and rosettes were cytokeratin AE1/AE3, Synaptophysin, Chromogranin A, CD56, NSE, and EMA positive, whereas the smaller cells were always negative. Interestingly smaller cells expressed only weak nuclear positivity for TTF1, whereas larger cells were TTF1 negative. Melanocytic markers were negative in both populations. Morphological patterns and immunohistochemical staining confirmed ocular ME and allowed to exclude pulmonary metastasis or primary malignant melanoma. The patient was successfully treated by brachytherapy alone and is alive and well 10 months after treatment. Diagn. Cytopathol. 2017;45:561–564. © 2017 Wiley Periodicals, Inc.     

Cytokeratin expression in epithelioid vascular neoplasms.

Seven epithelioid and eight non-epithelioid vascular tumors were studied by the avidin-biotin-peroxidase method for the presence of endothelial- and epithelial-associated markers, using Ulex europaeus agglutinin-1 (UEA-1) lectin, and antibodies directed against factor VIII-related antigen, (FVIII-RA), vimentin, keratin, carcinoembryonic antigen, and epithelial membrane antigen. The cases included four epithelioid hemangiomas, two epithelioid hemangioendotheliomas (EHE), one epithelioid angiosarcoma (EAS), four common non-epithelioid capillary hemangiomas, and four non-epithelioid angiosarcomas. Staining for FVIII-RA, UEA-1, and vimentin were observed in all cases. The EAS showed staining for keratin in formalin-fixed, paraffin-embedded sections and in frozen sections. Staining for keratin was also observed in frozen sections of one EHE. Both keratin-positive vascular tumors were confirmed with electron microscopy. Carcinoembryonic antigen and epithelial membrane antigen stains were negative in all cases. Our results show that the epithelioid vascular tumors EHE and EAS, in addition to staining for the endothelial markers and vimentin, may also express the epithelial marker keratin. This is important since these tumors may closely resemble carcinomas by routine light microscopy. This study further underscores the importance of using a broad panel of immunohistochemical markers in the diagnostic workup of soft-tissue neoplasms.     

Perivascular epithelioid cell tumour (PEComa) of the soft tissue

AIMS: PEComa is a rare tumour developing from perivascular epithelioid cells (PEC) and is characterised by positive immunoreactivity for HMB45. Since PEComas are tumours having both a spindle cell component and an epithelioid and giant cell component, as seen in many sarcomas, as well as having a wide distribution in various organs and soft tissue, we reviewed cases originally diagnosed as sarcomas of the soft tissue in our institution and screened them by immunostaining for HMB45. METHODS: Consecutive soft tissue sarcomas (31 tumours) retrieved from the Surgical Pathology file at our institution for a period of 3 years were submitted for immunostaining for HMB45. Cases with positive HMB45 immunostaining were submitted for further immunostaining for MART1, CD68, S100 protein, cytokeratin AE1/3, EMA, vimentin, MSA and CD117. RESULTS: Of 31 sarcomas, three tumours in the group of 11 malignant fibrous histiocytomas (MFH) and unclassified sarcomas showed positive immunoreactivity for HMB45 and MART1 in 1-25% of tumour cells. The three tumours were located in the lower extremities and measured 8, 11 and 12 cm in diameter. Patient gender male:female was 2:1 and ages were 46, 56 and 60 years. Microscopically, the tumours were composed of a variable proportion of spindled cells, multinucleated cells and epithelioid cells disposed in diffuse sheets or nests. Mitotic figures and necrosis were frequent. The immunoreactivity was diffuse for CD68, focal for AE3 and EMA, negative or focal for MSA and CD117, and negative for S100 and AE1. All three patients developed lymph node or distant metastases and died of the disease within 1-2 years. CONCLUSIONS: PEComa re-screened from the group of high grade sarcomas without definite differentiation range from pleomorphic to monomorphic cytohistopathological features. Immunostaining for HMB45 of unclassified sarcomas is useful for the classification of these tumours. They occur preferentially in the lower extremities and have a high malignant potential when associated with large size, tumoural necrosis and high mitotic activity.     

C-Kit-positive metastatic malignant pigmented clear-cell epithelioid tumor arising from the kidney in a child without tuberous sclerosis

We report the first pediatric case of malignant pigmented epithelioid clear-cell tumor arising from kidney; the lesion occurred in a 12-year-old girl without tuberous sclerosis. The tumor was widely metastatic to the retroperitoneum and chest, and the patient died of the disease 9 months after diagnosis, despite active chemotherapy. Pigmented epithelioid clear-cell tumor of the kidney is a rare variant of epithelioid angiomyolipoma and a member of the family of perivascular epithelioid cell tumors (PEComas). The tumor demonstrated overlapping features between clear-cell sugar tumor and epithelioid variant of angiomyolipoma. Tumor cells were positive for HMB-45 expression, negative for any evidence of muscular differentiation, and contained melanin pigment and premelanosomes in the cytoplasm. Diffuse C-Kit (CD117) positivity was identified throughout the tumor. This is the first report of C-Kit–positive malignant PEComas.     

肾脏上皮样血管平滑肌脂肪瘤的病理观察

目的对肾脏上皮样血管平滑肌脂肪瘤（epithelioid agiomyolipoma,EAML）的病理诊断、鉴别诊断和预后进行分析。方法2例肾脏EAML（其中1例为复发病例）,复习其临床资料,病理学检查包括常规病理学、免疫组织化学和超微结构,并进行随访。结果光镜下肿瘤均主要由具有多形性和不典型性的上皮样细胞组成,部分区域有明显的血管周上皮样排列;可见出血和坏死;并可见静脉内瘤栓;淋巴结内可见上皮样肿瘤细胞累及。免疫组织化学肿瘤细胞（包括淋巴结内肿瘤）HMB45、平滑肌肌动蛋白（SMA）、神经元特异性烯醇化酶（NSE）和波形蛋白弥漫阳性;S-100、melanpan和CD68散在阳性;而上皮细胞膜抗原（EMA）、AE1／AE3、CK7、CD117、肌肉特异性肌动蛋白（MSA）、结蛋白、白细胞共同抗原（LCA）、CD20、CIM5RO、CD30、CD15、嗜铬素（CgA）、突触素（Syn）、bcl-2、雌孕激素受体（ER、PR）和p53均为阴性。电镜检查可见一些肿瘤细胞内有黑色素小体样的致密颗粒、肌丝、密体,肿瘤细胞外可见不连续的基膜。2例患者手术后10个月状态良好,无肿瘤局部复发和转移征象。结论血管周上皮样排列、寻找经典血管平滑肌脂肪瘤的结构和肿瘤细胞表达HMIM5和SMA对于诊断和鉴别诊断至关重要。而细胞的不典型性、出血坏死和核分裂象可能只表明肿瘤的恶性潜能：淋巴结受累、肾静脉瘤栓不是恶性的诊断依据：只有远处转移才是恶性的证据。     

Klarzelltumor der Lunge

Clear cell tumors of the lung are rare tumors composed of epithelioid HMB45 positive tumor cells. It has been proposed that clear cell tumors generate from perivascular epithelioid cells which are also found in renal angiomyolipoma. Due to its morphologic epithelioid features with clear cytoplasm the distinction from either primary or metastatic clear cell carcinoma is difficult. Usually clinical investigations do not lead to the final diagnosis so that only subsequent histological examination and immunophenotyping can establish the correct tumor classification. We describe the case of a 52 year old woman who underwent exploratory thoracotomy because of a lung mass in the right lower lobe. In frozen sections a solid trabecular tumor was diagnosed, paraffin histology and immunohistochemistry revealed a clear cell tumor of the lung. The difficulty of the correct diagnosis of the clear cell tumor of the lung in frozen sections is discussed as well as the differential diagnosis.     

Perivascular epithelioid cell tumor of the rib

We present a rare case of perivascular epithelioid cell tumor (PEComa) in the right 6th rib of a 28-year-old man. A plain computed tomography scan showed a round osteolytic lesion in the right 6th rib. The resected tissue contained a globular-shaped, soft tumor. Histologically, the tumor was rich in vasculature and exclusively composed of perivascular epithelioid cells with clear cytoplasm. Immunohistochemically, the tumor expressed diffusely a melanocyte marker, human melanoma black-45, and focally a myogenic marker, alpha-smooth muscle actin, but not an epithelial marker, AE1/AE3. Fontana-Masson-positive melanin pigments were present and c-kit receptor tyrosine kinase (CD117), involved in the development of melanocytes but not myogenic cells, was expressed in tumor cells. These findings indicate that the tumor is PEComa with some differentiation into melanocytes. Notably, owing to the unique location of the occurrence, the tumor occupied bone marrow tissues of the rib, resulting that the tumor has the potential for hematogenous metastasis. In spite of the lack of cells with severe atypia, necrosis, and numerous mitoses, tumor cells invaded into surrounding tissues and overexpressed cyclin D1. To the best of our knowledge, this is the first case report of PEComa arising from the rib with the signs of malignant potential.     

Primary malignant neuroectodermal tumor of the ileum with predominantly uncommon pseudopapillary architecture

A malignant gastrointestinal neuroectodermal tumor (GNET), a distinctive entity covering the characteristics of clear cell sarcoma (CCS) of gastrointestinal tract described recently, arising primarily in the ileum of a 33-year-old woman is reported. Histologically, the neoplasm involved the full thickness of the intestinal wall. Tumor cells, mainly displayed epithelioid or polygonal appearance with oval or round nuclei, arranged in strand, nested, and solid pattern with prominent pseudopapillary architecture instead of the familiar histological image with multinucleated osteoclast-like giant cells. They were positive for vimentin, S-100, synaptophysin, CD56 and CD99 protein, but negative for AE1/AE3, EMA, CEA, LCA, Desmin, CK7, CK20, Villin, CgA, CD117, Dog-1, GFAP, Melan-A, HMB-45, CD34, CR, WT1, D2-40. Fluorescence in situ hybridization (FISH) showed the presence of chromosomal translocation involving EWSR. The patients lived through a calm period after a tumor resection and 4 cycles of chemotherapy combining ifosfamide and epirubicin. This case demonstrates that GNET is a rare tumor in gastrointestinal tract, and furthermore, various misleading histological characteristics should been taken into consideration in the diagnosis.     

Interdigitating dendritic reticulum cell sarcoma: cytologic, histologic and immunocytochemical features

Tumors of dendritic reticulum cells are rare neoplasms that exhibit significant morphologic overlap with other malignancies. Fine-needle aspiration cytologic appearances of this neoplasm are not well understood. A 33-yr-old woman presented with a rapidly growing nodular mass in the right upper cervical region and right-sided ptosis. Fine-needle aspiration cytology of the mass showed dissociated as well as clustered, large, polygonal cells that showed high nuclear-cytoplasmic ratio. Nuclei were round, oval, or irregular in shape. Large and small blastoid forms with prominent nucleoli and chromatin clumping as well as binucleated cells and cells with lobulated nuclei were seen. Numerous mitoses were observed. The tumor cells expressed focal immunocytochemical reactivity to CD45 and CD68, but were negative for CD2, CD3, CD4, CD8, CD20, CD30, CD45RO, epithelial membrane antigen (EMA), cytokeratin, and HMB45. Histologic sections of the biopsy from the growth showed nodal tissue effaced by a tumor composed of large, pleomorphic neoplastic cells with some binucleate and multinucleate forms resembling Reed-Sternberg cells. The intervening stroma contained numerous small lymphocytes. Tumor cells expressed vimentin, S-100 protein, CD68, and MAC387, but were negative for LCA, CD1a, CD3, CD15, CD20, CD21, CD23, CD30, CD35, carcino-embryonic antigen, HMB45, cytokeratin AE1/3, EMA, myeloperoxidase, lysozyme, smooth-muscle actin, and desmin. The combined histologic and immunohistologic features suggested a histiocytic/dendritic reticulum cell neoplasm and a diagnosis of interdigitating dendritic reticulum cell sarcoma was made.     

Epithelioid hemangioendothelioma with extensive cystic change and CAMTA1 rearrangement

Epithelioid hemangioendothelioma (EHE) is a rare vascular neoplasm that has the ability to recur locally and metastasize. Thus, it is important to distinguish this tumor from other epithelioid vascular neoplasms. A 47‐year‐old man presented to our hospital with a pelvic mass with severe ischialgia and weight loss. Surgical resection was performed, and the mass was found to have dark red multiloculated cysts with hemorrhage and calcification. The histopathologic examination showed a central sclerotic, hypocellular zone and a peripheral cellular zone. Only the peripheral portion of the wall revealed nested tumor cells in light blue myxoid stroma. These tumors are typically composed of short strands or cords of bland epithelioid cells with occasional intracytoplasmic lumens embedded in a myxohyalinized stroma. The tumor cells were positive for CD31 and CD34 and negative for factor VIII‐related antigen, CK (AE1/AE3) and S‐100. The tumor nuclei showed distinct break‐apart signals with individual green and/or red signals, indicating the presence of CAMTA1 rearrangement. In this study, we report a case of EHE that was difficult to diagnose based on histology alone. Therefore, we also performed fluorescence in situ hybridization, and found that the tumor harbored a CAMTA1 gene rearrangement, which confirmed the diagnosis.     

硬化性上皮样纤维肉瘤的临床病理学观察

目的探讨硬化性上皮样纤维肉瘤的临床病理学特征、免疫表型及鉴别诊断.方法应用光镜和免疫组织化学LSAB法对8例硬化性上皮样纤维肉瘤进行临床病理学分析和免疫表型检测.结果患者均为成年人,男性5例,女性3例,年龄35～54岁(平均45岁).临床上表现为深部软组织内缓慢性生长的肿块,其中大腿/臀部3例,右上臂/肩部2例,胸壁和背部2例,小腿1例.大体上,肿块呈结节状,境界相对清楚,直径2.0～10.5 cm(平均6 em),切面呈灰白色,质地坚韧或有弹性.组织学上,肿瘤由形态一致、小至中等大的圆形或多边形上皮样细胞组成,多呈单个或狭窄的条索状排列,夹杂于大量嗜伊红色、玻璃样变的胶原纤维之间.部分区域中也可排列成巢状、片状或腺泡状.高倍镜下,瘤细胞的胞质透亮或嗜伊红色,核异型性不明显,核分裂象也少见(＜1/10HPF).另在2例肿瘤的局部区域,细胞密度明显增加,核有显著的异型性,核分裂象也易见,类似经典的纤维肉瘤.免疫组织化学标记显示,瘤细胞弥漫强阳性表达波形蛋白,灶性或弱阳性表达上皮膜抗原,不表达细胞角蛋白、S-100蛋白、HMB45、肌动蛋白、结蛋白、CD34、bcl-2、CD30和白细胞共同抗原(LCA)等标记.随访6例,3例复发,1例发生肺部转移.结论硬化性上皮样纤维肉瘤是纤维肉瘤的一种少见亚型,尽管瘤细胞异型性不明显,核分裂象也少见,但肿瘤可发生局部复发及远处转移,临床上应视为一种低至中度恶性的软组织肉瘤处理,组织学上则应注意与一些具有上皮样形态和硬化性间质的肿瘤相鉴别.     

Duodenal gangliocytic paraganglioma: report of two cases and review of literature

We report two cases of Gangliocytic paraganglioma (GP), one of which was accompanied by lymph node metastasis. Histologically, the tumor was composed of three morphologically distinct cell populations: spindle cells, ganglion-like cells and epithelioid cells. The epithelioid cells were positive for cytokeratin (AE1/AE3), synaptophysin (Syn), chromogranin A (CgA), CD56 and progesterone receptor (PR). Ganglion-like cell types showed positive reactivity for Syn and CD56. In contrast, the spindle-shaped cells showed positive reactivity for S-100. The patient with lymph node metastasis has a good prognosis. Nonetheless, close surveillance is still necessary for patients with GP because a few cases of GP with regional lymph node metastasis and even distant metastasis have been published, including a malignant case of GP showing a lethal course.     

上皮样肉瘤样血管内皮瘤的临床病理学观察

目的 探讨上皮样肉瘤样血管内皮瘤的临床病理学特征和鉴别诊断.方法 回顾性分析3例上皮样肉瘤样血管内皮瘤的临床表现、组织学特点和免疫表型.结果 3例均发生于成年男性,分别因左颈部肿块、髂部疼痛和双侧颈肩区复发性肿块就诊.镜下观察肿瘤由梭形和上皮样的细胞组成,两种细胞在形态上有移行.瘤细胞呈片状、模糊结节状或交织条束状排列,间质伴有胶原化.1例于结节中央可见凝固性坏死,形态上类似上皮样肉瘤.3例肿瘤内均无明显的血管形成,但其中1例于局灶区域可见胞质内空泡形成,类似上皮样血管内皮瘤.免疫组织化学标记,瘤细胞同时表达上皮性标记和内皮标记.3例均经手术切除,其中2例患者术后恢复良好,随访18个月和14个月均健在,无局部复发或远处转移,另1例术后6年内复发5次.结论上皮样肉瘤样血管内皮瘤属于一种少见的中间型血管内皮瘤,兼具上皮样肉瘤和上皮样血管内皮瘤的部分形态.仅凭光镜形态有时较难确定其内皮细胞分化,必须借助于免疫组织化学标记.上皮样肉瘤样血管内皮瘤与上皮样血管内皮瘤关系较为密切,可能是后者的一种富于细胞性梭形细胞变型.

Abstract：

Objective To study the clinicopathologic features and differential diagnosis of epithelioid sarcoma-like hemangioendothelioma (ES-H). Methods The clinical, radiologic and pathologic features of three cases of ES-H were analyzed. Results All the 3 cases occurred in male adults. The age ranged from 44 to 53 years. The presentations included left neck mass, iliac pain and bilateral shoulder masses. Histologically, ES-H was composed of a mixture of spindle and epithelioid tumor cells. Transition between the two cell types was demonstrated. The tumor cells were arranged in compact sheets, vague nodules or intersecting fascicles, amongst a collagenous stroma. Central coagulative necrosis was identified in one case, reminiscent the morphology that seen in epithelioid sarcoma. There was no evidence of angiogenesis, though focal presence of intracytoplasmic vacuoles was seen in one case, as in classic examples of epithelioid hemangioendothelioma. Immunohistochemical study showed that the tumor cells expressed both epithelial (AE1/AE3, CAM5.2 and epithelial membrane antigen) and endothelial (CD31,Fli-1 and factor Ⅷ-related antigen ) markers. Two of the cases were also positive for CD34. All of the patients were treated by surgical resection. Two patients remain well at 14-month and 9-month follow up,respectively. The remaining patient had repeated local recurrences during a 6-year period. Conclusions ES-H represents a rare morphologic type of hemangioendothelioma. It has some overlapping histologic features with epithelioid sarcoma and epithelioid hemangioendothelioma. The endothelial nature of ES-H is difficult to be verified on the basis of morphologic examination alone. Confirmation of the diagnosis with immunohistochemistry is necessary. ES-H is likely related to epithelioid hemangioendothelioma and may represent a cellular spindie cell variant of epithelioid hemangioendothelioma.     

Clear cell sarcoma of soft tissue in right parapharyngeal region: report of a rare case

Clear cell sarcoma (CCS), initially named malignant melanoma of soft parts, is a rare malignant neoplasm typically involving deep soft tissue of the extremities, in close proximity to tendons and aponeuroses. Here we describe a case of clear cell sarcoma of the right parapharyngeal region in a young female aged 20 years. MRI detected a mass about 4.4 cm×3.4 cm×3.0 cm, located in the right parapharyngeal area and between the external pterygoid and the medial pterygoid. Microscopically, most of the tumor cells were epithelioid with palely eocinophilic cytoplasm arranged in sheets. Pleophorism of tumor cells were not marked. Immunohistochemical analysis shows that the tumor cells were positive for vimentin, S-100, HMB45 and MelanA, and negative for AE1/AE3, actin-sm, desmin, CD117, TFE-3, and P63. Ki67 index was about 5%.     

Fine‐needle aspiration diagnosis of high grade adenoid cystic carcinoma metastatic to the pancreas

Pancreatic tumors are mostly primary tumors, with only rare metastatic tumors described in the literature. Here we report an unusual case of fine‐needle aspiration (FNA) diagnosis of high grade adenoid cystic carcinoma of the parotid gland metastatic to the pancreas. The aspirate smears were moderately cellular and revealed numerous basaloid neoplastic cells. The cytomorphologic differential diagnosis included primary pancreatic tumor with small cell morphology as well as metastatic tumors. By immunocytochemistry, the tumor cells were positive for cytokeratins (AE1/AE3, CAM5.2, and CK7), and CD117 (C‐KIT), and negative for CD45, WT1, synaptophysin, chromogranin, CD56, TTF‐1, and CK20. The cytomorphologic features and immunoprofile in our case were consistent with high‐grade carcinoma metastases from patient's known salivary gland primary. To the best of our knowledge, this case is the first reported encounter of FNA diagnosis of pancreatic metastasis with small cell morphology from a salivary gland neoplasm as primary site. Diagn. Cytopathol. 2015;43:117–120. © 2014 Wiley Periodicals, Inc.