Retroperitoneal sclerosing PEComa with melanin pigmentation and granulomatous inflammation-A rare association within an uncommon tumor

ArticleinIndian Journal of Pathology and Microbiology 55(3):395-8 · July 2012with9 Reads
DOI: 10.4103/0377-4929.101757 · Source: PubMed
Abstract
PEComa, defined as a perivascular epithelioid cell tumor, displays a wide clinicopathological spectrum. Lately, a sclerosing PEComa has been identified as its distinct variant, but with limited documentation, in view of its rarity. Herein, we describe an uncommon case of a 53-year-old lady, who was referred to us with pain abdomen. Radiological imaging disclosed a well-defined, hypodense retroperitoneal mass. The excised tumor was a round, encapsulated soft tissue mass measuring 7 cm with a tan-brown cut surface. Microscopy showed uniform, epithelioid cells with clear cytoplasm, focal melanin pigmentation and mild nuclear atypia, arranged in sheets and nests around capillary-sized vessels in a dense sclerotic stroma. Additionally, co-existing epithelioid granulomas were noted. On immunohistochemistry (IHC), tumor cells were diffusely positive for HMB45; focally for desmin and smooth muscle actin (SMA), while negative for EMA, CD10, S100-P, Melan A, CD34, AMACR and CK MNF116. This case reinforces sclerosing PEComa as an uncommon, but a distinct clinicopathological entity and exemplifies diagnostic challenge associated with it; necessitating application of IHC markers for its correct identification. Presence of melanin pigment and granulomatous inflammation in the present tumor constitute as novel histopathological findings in a sclerosing PEComa.
    • "Sclerosing PEComa NA Slight enhancement NA Round-to-oval mass Rekhi et al, 7 2012 Retroperitoneal soft tissue (1) "
    [Show abstract] [Hide abstract] ABSTRACT: Perivascular epithelioid cell tumour is a relatively new entity with rising incidence. This is a rare mesenchymal neoplasm that can occur in various organs and is characterised by proliferation of perivascular cells and expression of myomelanocytic markers. Here, we present an asymptomatic 52-year-old female patient with an incidental radiological finding of a large retroperitoneal mass, histologically and immunohistochemically proven to be a sclerosing type of perivascular epithelioid cell tumour. The mass showed typical morphological and microscopic features consistent with those described in the current literature. However, it had computed tomography findings of neovascularisation and hyper-vascularity, not often documented in previous case reports of the sclerosing type of tumours. Literature review, using PubMed, of intraperitoneal / retroperitoneal type of tumours, and specifically the sclerosing type, was performed. To the best of our knowledge, less than 20 sclerosing perivascular epithelioid cell tumours have been reported and few describe the associated radiological features.
    Full-text · Article · Mar 2015 · Annals of diagnostic pathology
  • [Show abstract] [Hide abstract] ABSTRACT: Sclerosing perivascular epithelioid cell tumor (PEComa) is an unusual variant of PEComa that has a predilection for the retroperitoneum of middle-aged women. Sclerosing PEComas may also arise from the kidneys. This entity is a relatively indolent neoplasm for which surgery alone can be curative.
    Article · Oct 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Perivascular epithelioid cell tumors, or PEComas, are mesenchymal neoplasms composed of histologically and immunohistochemically distinctive epithelioid or spindle cells, which are immunoreactive for both smooth muscle and melanocytic markers. The cells in PEComas are typically arranged around blood vessels and appear to form the vessel wall, often infiltrating the smooth muscle of small- to medium-sized vessels. Periluminal cells are usually epithelioid and the more peripheral cells are spindle shaped. The cells have small, round to oval nuclei, sometimes with focal nuclear atypia, and clear to eosinophilic cytoplasm, and no counterpart normal cell has been identified. The PEComa "family" now includes angiomyolipoma, pulmonary clear cell "sugar" tumor and lymphangioleiomyomatosis, primary extrapulmonary sugar tumor, clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres, abdominopelvic sarcoma of perivascular epithelioid cells, and other tumors with similar features at various sites that are simply termed PEComa. Some PEComas occur in patients with tuberous sclerosis complex and share the genetic abnormalities. There is a behavioral spectrum from benign to frankly malignant, and histologic criteria have been proposed for assessing malignant potential. The differential diagnosis can include carcinomas, smooth muscle tumors, other clear cell neoplasms, and adipocytic tumors. PEComas constitute a genetically diverse group that includes neoplasms harboring TFE3 gene rearrangements and those with TSC2 mutations, indicating alternative tumorigenic pathways. Recent advances in therapy of malignant PEComas relate to increased knowledge of specific genetic changes and their effects on metabolic pathways that are susceptible to specific interventions. We review PEComas, emphasizing the diagnostic spectrum and recent immunohistochemical and genetic findings. Copyright © 2015. Published by Elsevier Inc.
    Article · Jun 2015
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