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

TFE3 -Rearranged PEComa/PEComa-like Neoplasms : Report of 25 New Cases Expanding the Clinicopathologic Spectrum and Highlighting its Association With Prior Exposure to Chemotherapy

Since their original description as a distinctive neoplastic entity, ~50 TFE3 -rearranged perivascular epithelioid cell tumors (PEComas) have been reported. We herein report 25 new TFE3 -rearranged PEComas and review the published literature to further investigate their clinicopathologic spectrum. Notably, 5 of the 25 cases were associated with a prior history of chemotherapy treatment for cancer. This is in keeping with prior reports, based mainly on small case series, with overall 11% of TFE3 -rearranged PEComas being diagnosed postchemotherapy. The median age of our cohort was 38 years. Most neoplasms demonstrated characteristic features such as nested architecture, epithelioid cytology, HMB45 positive, and muscle marker negative immunophenotype. SFPQ was the most common TFE3 fusion partner present in half of the cases, followed by ASPSCR1 and NONO genes. Four of 7 cases in our cohort with meaningful follow-up presented with or developed systemic metastasis, while over half of the reported cases either recurred locally, metastasized, or caused patient death. Follow-up for the remaining cases was limited (median 18.5 months), suggesting that the prognosis may be worse. Size, mitotic activity, and necrosis were correlated with aggressive behavior. There is little evidence that treatment with MTOR inhibitors, which are beneficial against TSC -mutated PEComas, is effective against TFE3 -rearranged PEComas: only one of 6 reported cases demonstrated disease stabilization. As co-expression of melanocytic and muscle markers, a hallmark of conventional TSC -mutated PEComa is uncommon in the spectrum of TFE3 -rearranged PEComa, an alternative terminology may be more appropriate, such as " TFE3 -rearranged PEComa-like neoplasms," highlighting their distinctive morphologic features and therapeutic implications.

Orbital Perivascular Epithelioid Cell Tumor in a Case of Tuberous Sclerosis

The aim of the study was to report a case of orbital perivascular epithelioid cell tumor (PEComa) in a known diagnosed patient of tuberous sclerosis and retinal astrocytic hamartoma. 43-year-old female presented with rapid progressive painful proptosis in the left eye, also reported new mass growing in her upper back. The patient past medical history is significant for left renal angiomyolipoma and multiple bilateral lung cysts of which she underwent right nephrectomy and lung biopsy, respectively. The lung biopsy turned diagnostic for lymphangiomyomatosis. On external examination, the left eye was grossly proptotic with hypoglobus. A typical butterfly distribution of sebaceous adenoma was noted across the patient cheeks and nose. Visual acuity in the right eye was 20/20 and the left eye, 20/25. Funduscopic examination identified type 1, 2, and 3 retinal astrocytic hamartomas. MRI brain and orbit was significant for a lesion arising from the lateral orbital wall with extensive bone destruction, displacing the left optic nerve medially. CT chest showed left extrathoracic mass had same radiological features as the orbital lesion; thus, an incisional biopsy performed on the former was diagnostic for PEComa with atypical features. This is the first observed case of PEComa in a known diagnosed patent with TS and retinal astrocytic hamartoma. The association of tuberous sclerosis complex and orbital PEComa is rarely and poorly reported in the literature compared to extraocular PEComa.

Conjunctival Perivascular Epithelioid Cell Neoplasm With RBM10-TFE3 Fusion Presenting as Recurrent Subconjunctival Hemorrhage

Subconjunctival hemorrhages commonly present to eye care professionals and are frequently regarded as benign self-limited conditions. In selected cases, subconjunctival hemorrhages can be a harbinger of more severe disease. Perivascular epithelioid cell tumors, or PEComas, are rare mesenchymal neoplasms believed to originate from perivascular myoid cells and are rarely present in ocular structures. We present a rare case of a conjunctival perivascular epithelioid cell tumor that initially presented with recurrent subconjunctival hemorrhage. To our knowledge, this is the first description of a PEComa with a RBM10-TFE3 gene fusion, only previously seen with renal cell carcinoma. Physicians should be aware of this rare condition, its location in the fornix and its presentation as a recurrent subconjunctival hemorrhage.