Giant Perivascular Epithelioid Cell Tumor of the Orbit: A Clinicopathological Analysis and Review of the Literature

Abstract

Aim: To describe and review the clinical, radiological, and histopathological characteristics of an orbital perivascular epithelioid cell tumor (PEComa). Methods: A systematic review of clinical records, radiological investigations, microscopic features, and immunohistochemical characteristics was done. Results: A 9-year-old female child presented with a year-long history of a large orbital mass associated with painless, progressive proptosis of the right eye. Radiologically, a well-defined orbital mass was seen with no intracranial extension. Excision was performed and histopathological examination showed uniform epithelioid cells in nests separated by thin fibrovascular septae. The tumor cells stained positively for Human Melanoma Black-45, but neg­atively for desmin, S-100, smooth muscle actin, MyoD1, microphthalmia-associated transcription factor, vimentin, CD10, CD31, and CD34 with a low proliferation index of 5–7%. Based on the tumor’s morphological and immuno­histochemical characteristics, a diagnosis of giant orbital PEComa was made. No recurrence was seen at the last follow-up. Conclusions: PEComas are uncommon mesenchymal neoplasms that have typical histological features, with an immunohistochemical profile of negativity for epithelial markers and positivity for melanocytic markers. For benign PEComas, complete excision is advised. However, since PEComas elsewhere in the body have been known to be malignant, a close follow-up of such cases is recommended.

Orbital TFE3-Rearranged Perivascular Epithelioid Cell Tumor: A Case Report and Review of the Literature

“…Rearrangements on the TFE3 gene, present on chromosome Xp11, are increasingly reported in PEComas. 1,6 TFE3 fusions induce upregulation of TFE3, a transcription factor of the MiT/TFE family involved in cell metabolism. They have been described in several types of neoplasia such as alveolar soft-part sarcoma and renal cell carcinoma.…”

“…The latter can be, in some cases, inhibited by sirolimus and its derivatives. 1,6 Although there is an association of AML and LAM with TSC, this association has been documented in ,10% of patients with PEComas of soft tissue and gynecologic origin. 1,6 In our case, neither the patient nor other family members exhibited any of the features of TSC.…”

“…4 Among all the locations, the eye and the orbit are rare sites, with only a few cases described. 2,[6][7][8][9] In this case report, we describe and discuss the clinical and histopathological features of a case of orbital PEComa.…”

Diagnosis and treatment of malignant PEComa tumours

“…The age of the patients at the time of PEComa diagnosis is most commonly in the range of 38.9-56 years [7,8], but PEComa cases in children have also been described [9,10]. All reviews indicate more common PEComa occurrence in women (54-86.9% of cases) [11,12], also after exclusion of sex-specific locations from the analysis [3].…”

“…In a large analysis 24 pancreatic PEComa cases were presented, of which half were localised in the head of the pancreas [12] and numerous PEComas of the digestive tract [11,15], including the stomach [16], the ileus [17] and the colon [18]. Moreover, single cases in various locations have been described: the greater omentum [19], the gall bladder [20], the common bile duct [21], the breast [22], the thigh bone [6], rib [23], skull base [24], heart [25], pericardium [26], the prostate [27,28], ovary [29], nasal cavity [30], throat [31], eye socket [10], urinary bladder [32], lung [33], and the groin [34].…”