Perivascular epithelioid cell tumour (PEComa) of the uterus associated with malignant neoplasm of the female genital tract

Systematic analysis of perivascular epithelioid cell neoplasms in the female reproductive tract: a comprehensive review

Perivascular epithelioid cell neoplasms (PEComas) are rare mesenchymal lesions, with gynecological PEComas accounting for just over a quarter of cases. Limited reports exist on gynecological PEComa, primarily treated with surgery; adjuvant therapy is considered in high-risk cases. This systematic review aims to summarize the origin and clinical, pathological and molecular characteristics of uterine PEComa, focusing on treatment options for gynecological PEComa. A comprehensive PubMed review of gynecological PEComa reports was conducted. A detailed examination of the literature ensured a thorough understanding. Gynecological PEComa diagnosis relies on histology and immunology. Despite therapy controversies, surgery remains the mainstay. Adjuvant therapy efficacy in high-risk cases is uncertain. mTOR inhibitors are the first line; alternative treatments, including angiogenesis and aromatase inhibitors, should be considered.

Uterine collision tumor (PEComa and endometrioid carcinoma) in a tuberous sclerosis patient: a case report

Perivascular epithelioid cell tumors are very rare mesenchymal neoplasms arising in various locations, such as the female genital tract, kidney, lung, prostate, bladder, pancreas, soft tissues, and bone. They possess a unique immunophenotype, co-expressing myogenic and melanocytic markers; molecular findings include mutations of tuberous sclerosis complex and translocations of transcription factor E3, a member of the microphthalmia transcription factor gene family. We herewith report a uterine collision tumor consisting of a perivascular epithelioid cell tumor and a moderately differentiated endometrial endometrioid carcinoma in a patient with genetically proven tuberous sclerosis; two leiomyomas were also found in contact with the tumor. Although two such cases one with a benign and another with a malignant perivascular epithelioid cell tumor have previously been reported, ours is, to our knowledge, the first reported in a tuberous sclerosis patient.

A Case of Malignant PEComa of the Uterus Associated with Intramural Leiomyoma and Endometrial Carcinoma

Perivascular epithelioid cell tumors (PEComas) refers to a family of mesenchymal neoplasms composed of angiomyolipomas, clear cell “sugar” tumors of the lung, and lymphangioleiomyomatoses. These tumors have a distinctive and common component of perivascular epithelioid cells that show an association with blood vessel walls and immunohistochemically display myomelanocytic differentiation. The unique neoplasms have been shown to have an expanded range through a variety of case reports, including visceral, intra-abdominal, soft tissue, and bone tumors. The retroperitoneum, abdominopelvic region, and uterus have been reported to be the most common sites. Most PEComas follow a benign course. However, reports of malignant PEComas are increasing. Many papers have described uterine PEComas, but to our knowledge, there have not yet been any reports of a malignant PEComa arising concomitant with another epithelial tumor and mesenchymal tumor. We report herein the case of a 67-year-old woman who experienced a malignant uterine PEComa infiltrating a preexisting intramural leiomyoma with synchronous well differentiated endometrial carcinoma and multiple liver and lung metastases.

Perivascular epithelioid tumours (PEComas) of the gynaecological tract

Perivascular epithelioid tumours (PEComas) of the gynaecological tract are rare tumours which were first recognised and diagnosed within the last 20 years. They represent a unique diagnostic challenge with regard to their accurate and reproducible distinction from more common entities such as smooth muscle tumours of the uterine corpus. In this review article, we trace the development of the concept of the PEComa tumour family, highlight what is known about extra-gynaecological tract PEComa at an immunohistochemical, molecular and therapeutic level and then present a summary of all reported cases of gynaecological tract PEComa to date. In the summary, we highlight rare subtypes of gynaecological tract PEComa and compare the performances of extant prognostic classification systems for malignancy in these tumours.

Primary perivascular epithelioid cell neoplasm (PEComa) of bone: report of two cases and review of the literature

Primary perivascular epithelioid cell neoplasms (PEComas) of bone are rare mesenchymal tumors. Histologically, they are composed predominantly of perivascular epithelioid cells and have the capacity to metastasize. PEComas have been reported within intra-abdominal and intra-pelvic organs. To the best of our knowledge, only seven primary PEComas of bone have been described in the English literature. We present two cases of PEComa of bone, one arising from the distal fibula and one from the acetabulum. Both were treated by surgical excision and one also received adjuvant chemotherapy.

Heterologous and rare homologous sarcomas of the uterine corpus: a clinicopathologic review

Pure sarcomas of the uterine corpus are uncommon, constituting less than 3% of all malignancies at this site, and most of them are leiomyosarcomas and endometrial stromal sarcomas. Rare histotypes of homologous sarcomas and heterologous sarcomas are occasionally encountered, and the absence of significant accumulated experience with these histotypes at this location may potentially raise diagnostic and patient management difficulties. In this article, the clinicopathologic attributes of all earlier reported sarcomas of the uterine corpus other than leiomyosarcomas and endometrial stromal sarcomas are summarized. Included are embryonal rhabdomyosarcoma, pleomorphic rhabdomyosarcoma, angiosarcoma, alveolar soft part sarcoma, malignant perivascular epithelioid cell tumors (PEComas), osteosarcoma, chondrosarcoma, liposarcomatous tumors, malignant extrarenal rhabdoid tumors, Ewing sarcoma/primitive neuroectodermal tumor, and other rare histotypes. Embryonal rhabdomyosarcoma (20%), Ewing sarcoma/primitive neuroectodermal tumor (17%), angiosarcoma (14%), and pleomorphic rhabdomyosarcoma (13%) appeared to be more common than the others, although there was no single overwhelmingly prevalent histotype in the group. A subset, including embryonal rhabdomyosarcoma, alveolar soft part sarcoma, and PEComas, peak in the premenopausal years, but most of the others were observed in postmenopausal women. Favorable outcomes have been reported for the patients diagnosed with alveolar soft part sarcoma, and the prognosis for their counterparts with PEComa remains a matter of debate. Multimodal therapeutic approaches to contemporary patients with embryonal rhabdomyosarcomas have resulted in significantly improved outcomes. Unfortunately, most of the other sarcomas have been associated with rapid tumor progression and unfavorable patient outcomes. The differential diagnosis for these sarcomas is often extensive and varies by histotype, but their accurate diagnosis fundamentally requires the careful exclusion of biphasic malignancies.

Perivascular epithelioid cell neoplasms: pathology and pathogenesis

This review article summarizes our current understanding of the clinical, pathologic, immunohistochemical, and genetic aspects of perivascular epithelioid cell neoplasms, a rare group of related tumors defined by both morphologic and immunophenotypic criteria.

Perivascular epithelioid cell neoplasms: a systematic review of prognostic factors

Perivascular epithelioid cell tumors (PEComas) are rare, soft tissue tumors characterized by epithelioid cells with clear or eosinophilic cytoplasm and a perivascular disbursement. We compiled the treatment and follow-up results from an extensive collection of reported gynecologic PEComa cases and statistically analyzed their respective therapy modalities and corresponding patient outcomes. In the group of patients with PEComa who received surgical management alone, there was a tendency for them to exhibit a lower disease recurrence rate. Conversely, patients with PEComa who initially received surgery and chemotherapy or radiation therapy were associated with a higher disease recurrence rate (P =.024). Metastatic involvement was related to higher patient mortality rates (P =.0001), although this finding was unrelated to treatment type. Surgical management alone may suffice for nonaggressive lesions, but chemotherapy and radiotherapy appear necessary for patients who present with high-risk histologic condition or metastatic disease. Because PEComas exhibit varying biologic behavior and an ill-defined presentation, the treatment for these lesions necessitates further evaluation.

Uterine PEComa: appraisal of a controversial and increasingly reported mesenchymal neoplasm

In recent years, a group of tumors that have been designated "perivascular epithelioid cell tumors" (PEComa) have been reported with increasing frequency from a wide variety of anatomic locations. The uterus and retroperitoneum appear to be the most frequent sites of origin for these lesions. PEComas belong to an identically named family of tumors comprised of conventional angiomyolipomas, clear cell sugar tumors, lymphangiomyomatosis and clear cell myomelanocytic tumor of the falciform ligament/ligament teres, and are also known as PEComa-NOS. This article is a primer for clinicians on the most salient clinicopathologic features of uterine PEComas, as most of the debate and discussion have taken place in the pathologic literature. The author appraises in detail the current state of knowledge on PEComas of the uterus based on a review of published data on the 44 previously reported cases, and comments on areas of controversy. The latter are centered predominantly on the significant morphologic and immunophenotypic overlap that exists between uterine PEComa and some smooth muscle tumors of the uterus. The clinicopathologic features of cases reported as epithelioid smooth muscle tumors and cases reported as uterine PEComas are compared and contrasted, and a practical approach to their reporting is proposed.

Perivascular epithelioid cell tumor (PEComa) of the uterus: an outcome-based clinicopathologic analysis of 41 reported cases

The uterus and retroperitoneum have emerged as the most frequently reported anatomic sites of origin of perivascular epithelioid cell tumors (PEComas), a poorly defined neoplasm that is characterized by varying amounts of spindle and epithelioid cells with clear to eosinophilic cytoplasm that display immunoreactivity for melanocytic markers, most frequently HMB-45. Published reports on 41 previously reported uterine PEComas are reviewed in this report. Of these 41 cases, 31 originating in the corpus and for which there was adequate follow-up information (or clinical malignancy) were categorized into 2 groups: (1) a malignant group that was comprised of cases associated with patient death of disease and/or clinical malignancy as evidenced by local and/or distant extension outside of the uterus (n=13, group 1) and (2) a "nonmalignant" group of cases in which neither of the above features were present (n=18, group 2). Groups 1 and 2 did not significantly differ regarding duration of follow-up (25 mo vs. 24.3 mo, respectively, P=0.9) or patient age (45.61 y vs. 43.46 y, respectively, P=0.7). Five of the group 1 patients experienced distant (extra-abdominal) metastases. The group 1 tumors were significantly larger than the group 2 tumors (averages 9.6 cm vs. 4.67 cm respectively, P=0.04); however, there were no size thresholds that, in of themselves, reliably classified 75% or more of the cases in both groups. Coagulative necrosis was highly associated with group 1, being present in 82% of cases as compared with only 11.8% of group 2 cases (P=0.0002). Eighty-eight percent of the group 2 cases had a mitotic rate of <or=1/10 high power fields (HPF) as compared with 40% of group 1 cases (P=0.01). However, the absence of mitotic activity did not rule out malignancy, as 2 of the group 1 cases lacked mitotic activity and displayed metastases. Twenty-five percent, 49%, 56%, 73%, and 100% of tested cases displayed immunoreactivity for CD10, desmin, vimentin, smooth muscle actin, and caldesmon, respectively. PEComas are tumors of uncertain histogenesis and malignant potential that seem to display some morphologic and immunophenotypic overlap with smooth muscle neoplasia. A mitotic count of >1/10 HPF and/or coagulative necrosis are features that, if present, raise the definite potential for aggressive behavior.

Perivascular epithelioid cell neoplasms (PEComas): four malignant cases expanding the histopathological spectrum and a description of a unique finding

Four cases of malignant PEComas were stained with smooth muscle actin, muscle specific actin, desmin, human melanoma black-45, melan-A, microphthalmia transcription factor, S100 and cyclin D1. One case was studied by electron microscopy (EM). Tumour locations were the thigh, elbow, retroperitoneum and bladder in association with a urachal cyst. There were two men and two women; the average age was 51.3 years, and the size ranged from 5.0-23.0 cm. In three cases, 50-95% of the tumour was composed of pleomorphic sarcomatous areas. All cases had at least focal clear-cell areas. One case showed a continuous single layer of perivascular clear cells remote from the tumour, transitioning to invasive nests and to PEComa. EM demonstrated these cells in apposition to and in direct contact with the abluminal surface of the basal lamina of the capillaries. We suggest the term "pecosis" for these areas. All cases were positive for two or more melanocytic markers and for at least one actin. S100 and desmin were focally positive in one case. Cyclin D1 was positive in 3:4 cases. Four cases of malignant PEComa are described with the existence of a unique lesion (pecosis) in one case. These tumours may manifest largely as sarcomas appearing to be undifferentiated and should be considered in their differential diagnosis.

Perivascular epithelioid cell neoplasms of soft tissue and gynecologic origin: a clinicopathologic study of 26 cases and review of the literature

PEComas, occasionally associated with the tuberous sclerosis complex, are defined by the presence of perivascular epithelioid cells that coexpress muscle and melanocytic markers. This family of tumors includes angiomyolipoma (AML), clear cell sugar tumor of the lung (CCST), lymphangioleiomyomatosis (LAM), and very rare tumors in other locations. Because non-AML/non-LAM PEComas are extremely rare and their natural history and prognostic features undefined, we present our experience with 26 PEComas of soft tissue and the gynecologic tract, the largest series to date. We also performed a detailed review of the literature, with special attention to features predictive of clinical behavior. All PEComas exclusive of AML and LAM were retrieved from our consultation files. Immunohistochemistry for pan-cytokeratin (CK), S-100 protein, smooth muscle actins (SMA), desmin, vimentin, HMB45, Melan-A, microphthalmia transcription factor (MiTF), TFE3, CD117, and CD34 was performed. Clinical follow-up information was obtained. Fisher's exact test was performed. The median patient age was 46 years (range, 15-97 years); there was a marked female predominance (22 females, 4 males). Sites of involvement included the omentum or mesentery (6 cases), uterus (4 cases), pelvic soft tissues (3 cases), abdominal wall (2 cases), uterine cervix (2 cases), and vagina, retroperitoneum, thigh, falciform ligament, scalp, broad ligament, forearm, shoulder, and neck (1 case each). The tumors ranged from 1.6 to 29 cm in size (median, 7.8 cm). Tumors were epithelioid (N = 9), spindled (N = 7), or mixed (N = 10). Multinucleated giant cells were present in 18 cases. High nuclear grade was noted in 10 cases, high cellularity in 7 cases, necrosis in 8 cases, and vascular invasion in 3 cases. Mitotic activity was 0 to 50 mitotic figures (MF)/50 high power fields (HPF) (median, 0 MF/50 HPF) with atypical MF in 6 cases. IHC results were: SMA (20/25), desmin (8/22), HMB45 (22/24), Melan-A (13/18), MITF (9/18), S-100 protein (8/24), CK (3/23), vimentin (12/14), TFE3 (5/17), c-kit (1/20), and CD34 (0/7). Clinical follow-up (24 of 26 patients, 92%; median, 30 months; range, 10-84 months) showed 3 local recurrences and 5 distant metastases. At last available clinical follow-up, 2 patients (8%) were dead of disease, 4 patients (17%) were alive with metastatic or unresectable local disease, and 18 patients (75%) were alive with no evidence of disease. No patient in our series had a history of tuberous sclerosis complex. Recurrence and/or metastasis was strongly associated tumor size > median size (8 cm), mitotic activity greater than 1/50 HPF, and necrosis. We conclude that PEComas of soft tissue and gynecologic origin may be classified as "benign," "of uncertain malignant potential," or "malignant." Small PEComas without any worrisome histologic features are most likely benign. PEComas with nuclear pleomorphism alone ("symplastic") and large PEComas without other worrisome features have uncertain malignant potential. PEComas with two or more worrisome histologic features should be considered malignant. Occasional PEComas express unusual markers, such as S-100 protein, desmin, and rarely CK. The role of TFE3 in PEComas should be further studied.

The application of immunohistochemistry in the diagnosis of bone tumors and tumor-like lesions

Immunohistochemistry (IHC) plays an important role in the diagnosis of some bone tumors, especially in the differential diagnosis of primary from metastatic non-osseous tumors and in the categorization of small-round-blue-cell tumors. This article reviews immunomarkers used in bone tumors and their diagnostic significance.

Perivascular Epithelioid Cell Tumor of the Uterus: Report of Four Cases

Uterine perivascular epithelioid cell tumor (PEComa) is very rare, and there have been only 27 reported cases. The differentiation of the tumor has been enigmatic, and the biologic behavior remains unclear. This study describes the clinical, histologic, and immunohistochemical features of four cases of uterine PEComa. The patients were 30, 32, 36, and 40 years old, and none of them had tuberous sclerosis complex. The size of the tumors ranged from 1 to 30 cm in diameter, and 3 of the 4 tumors were confined in the uterus. One tumor involved the left ovary and omentum. Microscopically, the tumors were characterized by an epithelioid arrangement of tumor cells, which had abundant clear to eosinophilic pale granular cytoplasm, and one tumor had moderately atypical nuclei. Coagulative necrosis was found in two cases. The mitotic figures ranged from 0 to 11 per 10 high power fields. Immunohistochemically, the tumors were positive for vimentin (4/4), HMB45 (4/4), h-caldesmon (4/4), alpha-smooth muscle actin (3/4), muscle actin (2/4), and desmin (3/4). They were uniformly negative for Melan A, CD10, and S-100 protein. Ultrastructural examinations were performed on one case and revealed no melanosomes, premelanosomes, or evidence of smooth muscle differentiation. One patient died of intestinal metastases 17 months after surgery. The other patients have been well with no evidence of disease 8, 12, and 36 months after surgery. Uterine PEComa should be regarded as tumors with an uncertain malignant potential until long-term outcome data for a larger number of patients become available.

Perivascular epithelioid cell tumor (PEComa) of the uterine cervix associated with intraabdominal "PEComatosis": A clinicopathological study with comparative genomic hybridization analysis

Background

The World Health Organization recently recognized a family of neoplasms showing at least partial morphological or immunohistochemical evidence of a putative perivascular epithelioid cell (PEC) differentiation. These tumors include angiomyolipoma (AML), clear cell "sugar" tumors of the lung (CCST), lymphangioleiomyomatosis (LAM), clear cell myomelanocytic tumors of the falciform ligament and distinctive clear cell tumors at various other anatomic sites.

Case presentation & methods

A 41-year old gravida-1 para-1 with tuberous sclerosis presented with an incidentally identified 2.2 cm mass. The morphology and immunohistochemical profile was consistent with PEComa. Distinct aggregates of HMB-45 epithelioid cells were present in an occasionally distinctive perivascular distribution in the myometrium, small bowel lamina propria and ovarian hila. These distinctive aggregates, for which we propose the designation "PEComatosis" based on their intraabdominal distribution, did not display cytological atypia, mitotic activity or necrosis. CGH and DNA ploidy analysis showed a balanced chromosomal profile and diploid nuclei, respectively. There was no recurrence or metastases at 35 months' follow-up. Fifty-one previously reported cases of non-AML, LAM and CCST PEComas [perivascular epithelioid cell tumors- not otherwise specified (PEComa-NOS)] are reviewed.

Conclusions

The lesions may be a reflection of tumor multicentricity, in which each may be a potential nidus for the development of future more well-developed tumors. Alternatively, they may be a manifestation of a poorly understood "field effect", in which there is an increased propensity to develop tumors of this type throughout the abdomen. Finally, and least likely in our opinion, they may represent tumor spread from its primary site.