Perivascular epithelioid cell tumor, not otherwise specified: a clinicopathologic and immunohistochemical analysis of 31 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic characteristics of perivascular epithelioid cell tumor (PEComa), not otherwise specified (NOS) and to evaluate the diagnostic criteria for malignancy.</p><p><b>METHODS</b>The clinical and pathologic features of 31 cases of PEComa-NOS were reviewed. The follow-up data available were analyzed.</p><p><b>RESULTS</b>There were a total of 24 females and 7 males. The age of the patients ranged from 13 to 66 years (mean = 40 years). The site of tumor occurrence included gynecologic organs (n = 12), intraabdominal/peritoneal soft tissue (n = 10), gastrointestinal tract (n = 4), thigh (n = 2), mediastinum (n = 1), left groin (n = 1) and urinary bladder (n = 1). None of the cases was associated with tuberous sclerosis complex. Histologic examination showed that 23 cases (74%) were clear cell sugar tumor-like, 4 cases (13%) were clear cell myomelanocytic tumor-like and 4 cases (13%) were of mixed epithelioid-spindled morphology. According to the classification system proposed by Folpe et al, 19 cases (61%) were classified as malignant, 7 cases (23%) as PEComa of uncertain malignant potential and 5 cases (16%) as benign. The expression rates of HMB45, smooth muscle actin and desmin in tested cases were 100% (31/31), 67% (14/21) and 6/18, respectively. Follow-up data (1 to 56 months) were available in 23 cases (74%). Amongst the 16 cases of malignant PEComa, 7 patients were still alive with no evidence of disease, 6 patients were alive with unresectable or recurrent/metastatic disease and 3 patients died of the disease. The local recurrence and metastasis in those 16 cases were 6 cases and 5 cases, respectively. One of the 4 patients with PEComa of uncertain malignant potential died, while the remaining 3 patients and all of the patients with benign PEComa had an uneventful clinical course.</p><p><b>CONCLUSIONS</b>The classification system of PEComas proposed by Folpe et al. is reliable in routine practice. Correlation with the clinical and radiologic findings however is prudent when dealing with core biopsy specimens or sampling from exploration laparotomy. Owing to the histologic heterogeneity of this entity, thorough understanding of the morphologic spectrum is essential in arriving at a correct diagnosis.</p>

Epithelioid sarcoma-like hemangioendothelioma: a clinicopathologic and immunohistochemical study of 3 cases / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the clinicopathologic features and differential diagnosis of epithelioid sarcoma-like hemangioendothelioma (ES-H).</p><p><b>METHODS</b>The clinical, radiologic and pathologic features of three cases of ES-H were analyzed.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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 spindle cell variant of epithelioid hemangioendothelioma.</p>