Malignant PEComa of the adrenal gland

Massive simultaneous hepatic and renal perivascular epithelioid cell tumor benefitted from surgery and everolimus treatment: A case report

BACKGROUND

Perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm that predominantly affects the kidney and uterus. The occurrence of this tumor in the liver, particularly with simultaneous involvement of the liver and kidney, is exceedingly uncommon. Pathological diagnosis is the gold standard. PEComas usually show positive immunohistochemical staining for melanocytic (HMB-45, Melan-A) and myoid (SMA, muscle-specific actin) markers.

CASE SUMMARY

We presented a noteworthy case of malignant PEComa affecting both the liver and kidney in a 53-year-old man with tuberous sclerosis complex (TSC). FAT2 and TP73 mutations in the kidney were identified and positive expression of diagnostic markers including HMB-45, Melan A, and TFE3 were detected. In addition, we demonstrated that hepatic artery perfusion chemotherapy was ineffective for hepatic PEComa, while surgery remained the most effective approach. Everolimus showed an excellent efficacy in the postoperative treatment of the tumor.

CONCLUSION

Surgical treatment is preferred for malignant PEComa affecting liver and kidney, especially with TSC; everolimus is effective postoperatively.

Metastatic Adrenal PEComa: Case Report and Short Review of the Literature

PEComa has become a widely accepted entity, and increased recognition has led to descriptions of this tumor in a wide variety of anatomic sites, including the adrenal gland. PEComa (perivascular epithelioid cell tumor) is a mesenchymal tumor composed of perivascular cells, and the most frequent sites of PEComas are the uterus and retroperitoneum. The incidence is <1 per 1,000,000 people. We report a case of adrenal metastatic PEComa in a 63-year-old man discovered by a spontaneous hematoma of the rectus abdominis. In our case, PEComa of the adrenal gland was a significant diagnostic dilemma as the morphologic and immunophenotypic features of this neoplasm may easily be confused with those of other more commonly encountered lesions.

Surprising genetic and pathological findings in a patient with giant bilateral periadrenal tumours: PEComas and mutations of PTCH1 in Gorlin-Goltz syndrome

Gorlin-Goltz syndrome (GGS) or nevoid basal cell carcinoma syndrome is a rare tumour-overgrowth syndrome associated with multiple developmental anomalies and a wide variety of tumours. Here, we describe a case of a man aged 23 years with GGS with bilateral giant tumours adjacent to both adrenals that raised the suspicion of malignancy on imaging. Histological analysis of both surgically resected tumours revealed perivascular epitheloid cell tumours (PEComas) that were independent of the adrenals. Exome sequencing of the patient’s blood sample revealed a novel germline heterozygous frameshift mutation in the PTCH1 gene. As a second hit, a somatic five nucleotide long deletion in the PTCH1 gene was demonstrated in the tumour DNA of both PEComas. To the best of our knowledge, this is the first report on PEComa in GGS, and this finding also raises the potential relevance of PTCH1 mutations and altered sonic hedgehog signalling in PEComa pathogenesis. The presence of the same somatic mutation in the bilateral tumours might indicate the possibility of a postzygotic somatic mutation that along with the germline mutation of the same gene could represent an intriguing genetic phenomenon (type 2 segmental mosaicism).

A Primary Adrenal Epithelioid Angiomyolipoma (PEComa) in a Patient with Tuberous Sclerosis Complex: Report of a Case and Review of the Literature

Epithelioid angiomyolipomas (EAMLs) are mesenchymal tumors that are part of the family of the perivascular epithelioid cell neoplasms (PEComas). These tumors portray a potential aggressive behavior with metastatic lesions found in around 30% of reported cases. EAMLs might present sporadically or in association with the tuberous sclerosis complex (TSC). They typically involve the kidneys, liver, and lungs. It is extremely rare for these tumors to arise from other organs. The present report describes an unusual case of an adult patient with a history of TSC who developed EAML of the adrenal gland. Moreover, he presented with metastatic disease to the liver, a feature rarely described. The diagnosis of EAMLs can be challenging as they are hard to distinguish from other adrenal or renal tumors without a thorough histopathologic and immunohistochemical evaluation. Due to the potential aggressive behavior of these malignancies, timely diagnosis is extremely important and has significant therapeutic and prognostic implications.

Perivascular Epithelioid Cell Tumor of the Urinary Bladder: A Systematic Review

Perivascular epithelioid cell tumor (PEComa) of the urinary bladder is a rare neoplasm showing distinct melanocytic and smooth muscle differentiation. We aimed to review the clinicopathologic features of bladder PEComa using all the available cases in the literature, along with 2 new cases from our database. The patients included 15 females and 15 males with a mean age of 39.2 ± 15.3 years. Painless hematuria was the most common clinical presentation. The tumors were usually well circumscribed with a mean tumor size of 4.4 ± 2.7 cm. Bladder PEComas demonstrated nests, trabeculae, or sheets of epithelioid cells with intermixed spindled cells and numerous thin-walled vessels. Immunohistochemical studies showed that the tumors were positive for HMB45 (27/27), cathepsin (4/4), SMA (20/22), and caldesmon (3/3) and were negative for pan cytokeratin (0/18) and EMA (0/4). Molecular studies revealed that PEComa was associated with the TFE3 (n = 3) and EWSR1 (n = 1) gene rearrangements. Treatment included partial cystectomy (n = 18), transurethral resection (n = 8), and radical cystectomy (n = 4). Twenty patients had no evidence of disease during a mean follow-up time of 19.4 ± 17.2 months. Two patients had recurrence, and 1 patient died of metastatic disease. In conclusion, bladder PEComas demonstrate distinct morphologic and immunohistochemical features. Although most tumors follow a benign course, a small subset may develop metastasis and cause death.

Immunohistochemical Biomarkers of Mesenchymal Neoplasms in Endocrine Organs: Diagnostic Pitfalls and Recent Discoveries

Mesenchymal neoplasms rarely present in or adjacent to endocrine organs. In this context, the recognition of these rare tumor types can be challenging, with significant potential for misdiagnosis as sarcomatoid carcinomas (i.e., anaplastic thyroid carcinoma and sarcomatoid adrenal cortical carcinoma) or neuroendocrine carcinomas, depending upon the dominant histologic patterns. In this review, we address potential pitfalls in diagnosing selected mesenchymal neoplasms arising within or near endocrine organs, including dedifferentiated liposarcoma, synovial sarcoma, angiosarcoma, PEComa, proximal-type epithelioid sarcoma, Ewing sarcoma, and neuroblastoma. For each of these tumor types, we review clinical and pathologic features, histologic clues to distinguish them from endocrine neoplasms, and recently developed immunohistochemical markers that can be particularly useful for establishing the correct diagnosis.

Hepatic falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors

Background

The objective of the study was to explore the clinical expression, radiological and pathological features, differential diagnosis, and biological behavior of a clear cell myomelanocytic tumor. In a case involving a clear cell myomelanocytic tumor located in the hepatic falciform ligament, we evaluated clinical expression, radiological characteristics, histopathology, immunohistochemistry, and biological behavior; we also reviewed the relevant literature.

Case presentation

Clear cell myomelanocytic tumor is a benign soft-tissue neoplasm that often occurs in women, and is expressed as a painless mass. The falciform ligament is its most frequent site of occurrence. The imaging characteristics of this lesion were uneven enhancement in the arterial phase, continuing to strengthen in the venous phase, and equal density in the balance phase. Histological and immunohistochemical analysis revealed the main transparent epithelioid cells and smooth muscle spindle cells to be HMB-45(+), smooth muscle actin(+), and melan-A (+).

Conclusion

Hepatic vascular epithelioid cell tumors are very rare mesenchymal neoplasms. Few studies have investigated this tumor in the hepatic falciform ligament; consequently, its diagnosis and the selection of an appropriate treatment and follow-up protocol are challenging. Treatment outcome remains unpredictable. Therefore, clear cell myomelanocytic tumor should be viewed as a tumor with uncertain malignant potential requiring long-term follow-up.

PEComa: morphology and genetics of a complex tumor family

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.

Malignant Perivascular Epithelioid Cell Tumor (PEComa) of the Adrenal Gland: Report of a Rare Case Posing Diagnostic Challenge with the Role of Immunohistochemistry in the Diagnosis

Histological diagnosis of adrenal tumors is often challenging as diverse groups of tumors, both primaries and metastatic, may be seen in the adrenal gland with overlapping morphological features. Immunohistochemistry (IHC) plays the most important role in their diagnosis. Perivascular epithelioid cell tumor (PEComa), a rarely reported tumor in the adrenal gland, shares many features with another rare tumor sarcomatoid adrenocortical carcinoma (ACC). Extensive immunohistochemical study is required to distinguish this tumor from adrenocortical carcinoma and from other morphologically similar tumors. The unique combination of immunoreactivity for melanocytic markers, such as HMB-45 and Melan A, and myogenic markers, such as smooth muscle actin, is the hallmark of PEComas biological behavior, and prognosis of malignant PEComas is yet to be fully understood. Few cases of malignant PEComa have been reported in the adrenal gland. We report a case of malignant PEComa of the adrenal gland posing diagnostic challenge and compare its morphological and immunohistochemical features with those of sarcomatoid ACC.