Perivascular Epithelioid Tumor Research Articles

Tuberous Sclerosis Complex With Multiple Organ Tumors: Case Report and Literature Review

Pancreatic neuroendocrine neoplasms (PNEN) are tumors that originate from neuroendocrine cells. Only about 1% patients are related to mutation of tuberous sclerosis complex gene. Here, we reported a rare case with involvement of multiple organs and space-occupying lesions. Initially, the patient was thought to have metastasis of a pancreatic tumor. However, the patient was diagnosed as pancreatic neuroendocrine tumors, liver perivascular epithelioid tumors, splenic hamartoma, and renal angiomyolipoma by pathological examination after surgery. We performed genetic mutation detection to identify that tuberous sclerosis complex 2 gene presented with a heterozygous variant. Tuberous sclerosis often presents with widespread tumors, but it is less common to present with pancreatic neuroendocrine tumors and liver perivascular tumors as highlighted in the case. So we analyzed the relationship between TSC gene mutations and related tumors. And we also reviewed the current molecular mechanisms and treatments for tuberous sclerosis complex.

Leiomyoma with nuclear atypia: Rare diseases that present a common diagnostic problem.

Leiomyoma with nuclear atypia describes a group of uterine smooth muscle tumors with a wide range of histologic and clinical presentations and remarkable nuclear atypia. These include fumarate hydratase-deficient leiomyoma (FH-LM), intravenous leiomyomatosis (IV-LM), and leiomyoma with bizarre nuclei (LM-BN). Other uterine mesenchymal tumors, such as perivascular epithelioid tumor (PEComa) and inflammatory myofibroblastic tumors (IMFT) are the mimickers of leiomyoma with nuclear atypia. LM-BN is the primary tumor model with a long history in gynecologic pathology, but the histogenesis of LM-BN remains largely unknown. Differentiating LM-BN from other benign variants, tumors with uncertain malignant potential (STUMP), or fully malignant leiomyosarcoma (LMS) can be diagnostically challenging. Recent progress has improved the diagnosis of many types of leiomyoma with nuclear atypia based on their specific histology and molecular alterations. LM-BN is now a diagnosis of exclusion. In this article, I review the history of leiomyoma with nuclear atypia and compare the clinical, histologic, and molecular features of LM-BN with those of its mimics. In particular, I highlight the current progress made in molecular genetics and pitfalls in the diagnosis of different myogenic tumors with nuclear atypia.

Tuberous Sclerosis: Current Update.

Tuberous sclerosis complex (TSC) is a relatively rare autosomal dominant neurocutaneous disorder secondary to mutations in the TSC1 or TSC2 tumor suppressor genes. Although manifestation of the classic triad of seizures, intellectual disability, and facial angiofibromas may facilitate timely diagnosis of TSC, the multisystem features that may indicate TSC in the absence of these manifestations remain highly variable. In addition, patients with TSC are at risk of developing multiple benign and malignant tumors in various organ systems, resulting in increased morbidity and mortality. Thus, imaging plays a critical role in diagnosis, surveillance, and management of patients with TSC. It is crucial that radiologists be familiar with TSC and the various associated imaging features to avoid a delayed or incorrect diagnosis. Key manifestations include cortical dysplasias, subependymal nodules, subependymal giant cell astrocytomas, cardiac rhabdomyomas, lymphangioleiomyomatosis, and angiomyolipomas. Renal angiomyolipomas in particular can manifest with imaging features that mimic renal malignancy and pose a diagnostic dilemma. Other manifestations include dermatologic and ophthalmic manifestations, renal cysts, renal cell carcinomas, multifocal micronodular pneumocyte hyperplasia, splenic hamartomas, and other rare tumors such as perivascular epithelioid tumors. In addition to using imaging and clinical features to confirm the diagnosis, genetic testing can be performed. In this article, the molecular pathogenesis, clinical manifestations, and imaging features of TSC are reviewed. Current recommendations for management and surveillance of TSC are discussed as well. ©RSNA, 2021.

Tumor ovárico semejante a tumor de células epitelioides perivasculares (PEComa) en boga (Leporinus obtusidens)

Domitrovic, H.A.; González, A.O.; Flores Quintana, C.I.; Rosciani, S.A.; Hernández, D.R.: Tumor ovárico semejante a tumor de células epitelioides perivasculares (PEComa) en boga (Leporinus obtusidens). Rev. vet. 26: 1, 63-68, 2015.

Incidental perivascular epithelioid cell tumor in an inguinal hernia sac

Perivascular epithelioid tumors (PEComa) are uncommon mesenchymal neoplasms demonstrating positivity for muscular and melanocytic immuno-markers. Included in this category are angiomyolipoma, lymphangioleiomyomatosis, and clear cell sugar tumors. Lesions which do not fit into these categories are classified as “not otherwise specified”. We present a case of an incidentally discovered PEComa within inguinal hernia sac contents in a 70-year-old woman. It consisted of spindled and epithelioid cells with bland oval nuclei, small nucleoli and clear to light eosinophilic cytoplasm. There was no atypia or mitoses. The lesion was strongly positive for HMB45 and smooth muscle actin. Pelvic soft tissue and peritoneal PEComas are rarely reported in literature and very little is known about their prognosis. We discuss the immunohistochemistry, differential diagnosis, and pathogenesis of PEComas.

A Lymphatically Metastasized Perivascular Epithelioid Cell Tumor from the Uterus

Perivascular Epithelioid tumor (PEComa) is a rare malignancy which may occur at various anatomic sites. A case is described of PEComa in multiple lymph nodes in a 34 year old woman with adenocarcinoma of the cervix. Laparoscopic pelvic lymph node dissection revealed perivascular epithelioid tumor cells in 15/34 pelvic lymph nodes and no sign of the adenocarcinoma. At subsequent radical hysterectomy the primary tumor was found in the uterus, besides the stage IB1 adenocarcinoma of the cervix. No adjuvant treatment was given and the patient remained well, until the time of evaluation, 20 months after diagnosis. A systematic review is performed about gynecological PEComa with lymphatic involvement concerning diagnosis, treatment and overall survival.

Perivascular epithelioid cell tumor of abdominal origin

Perivascular epithelioid tumor is not a common disease; therefore, large series are not available in the literature, and most are case reports. Histologic characteristics of these neoplasms are positivity to melanogenic (HMB-45) and muscle stains. All these neoplasms have the characteristic perivascular epithelioid cell or "PEC," but the term myomelanocyte tumor has been proposed because of the immunohistochemistry expression. Females are affected more commonly than males. The uterus seems to be one of the most common organs affected. Its clinical behavior is uncertain, and standard treatment has not been established as well as criteria for malignancy. We report 3 cases of abdominal PEComa, 1 of them with benign clinical outcome and 2 with an aggressive behavior.

Tumor epitelioide perivascular uterino. Utilidad de la tomografía por emisión de positrones con 18F-fluordesoxiglucosa en su estadificación y seguimiento

Perivascular epithelioid tumors (PEComas) are a rare group of mesenchymal neoplasms with an unpredictable natural history and uncertain malignant potential. Uterine involvement and their association with tuberous sclerosis are typical for these tumors. We present a case of a 40-year old patient who was incidentally diagnosed of a uterine PEComa and serial studies of PET-CT with FDG were performed for staging and therapeutic response assessment. FDG PET-CT proved to be a valuable tool for detecting unsuspected pulmonary metastases and defining the reassessment of the patient after chemotherapy. The findings suggest that since this is a rare tumor, which does not always have benign behaviour, PET-CT may be a useful diagnostic imaging procedure for staging and clinical monitoring of patients who suffer this type of tumors.

Perivascular epithelioid tumors: Utility of the positron emission tomography with 18F-fluorodesoxyglucose (PET-TAC FDG) in their staging and follow-up

Perivascular epithelioid tumors (PEComas) are a rare group of mesenchymal neoplasms with an unpredictable natural history and uncertain malignant potential. Uterine involvement and their association with tuberous sclerosis are typical for these tumors. We present a case of a 40-year old patient who was incidentally diagnosed of a uterine PEComa and serial studies of PET-CT with FDG were performed for staging and therapeutic response assessment. FDG PET-CT proved to be a valuable tool for detecting unsuspected pulmonary metastases and defining the reassessment of the patient after chemotherapy. The findings suggest that since this is a rare tumor, which does not always have benign behavior, PET-CT may be a useful diagnostic imaging procedure for staging and clinical monitoring of patients who suffer this type of tumors.

Perivascular epithelioid cell tumor (PEComa) of the pancreas: Immunoelectron microscopy and review of the literature

A perivascular epithelioid tumor (PEComa) is a rare tumor probably arising from the perivascular epithelioid cells. Only three cases of pancreatic PEComa have been reported in the English-language literature. The present report describes an extremely rare case of pancreatic PEComa. A 47-year-old Japanese woman complained of lower abdominal pain and a well-demarcated solid tumor was found in the pancreatic head. There was no history of tuberous sclerosis complexes. Pylorus-preserving pancreaticoduodenectomy was thus performed. There was a well-demarcated, solid tumor measuring 17 mm in the pancreatic head. The tumor was composed of a diffuse proliferation of epithelioid tumor cells with many blood vessels but no adipose tissue. The tumor cells expressed HMB45 and alpha-smooth muscle actin. Ultrastructurally, the tumor cells possessed many membrane-bound granules that were positive for HMB45 on immunoelectron microscopy. The results of immunoelectron microscopy show that some PEComas possess not only typical melanosomes or premelanosomes but also aberrant melanosomes.

ACUTE LYMPHOBLASTIC LEUKEMIA SECONDARY TO CHEMORADIOTHERAPY FOR PERIVASCULAR EPITHELIOID CELL TUMOR OF UTERUS

Acute lymphoblastic leukemia (ALL), a primary hematologic malignancy that is especially common in childhood, occurs relatively rarely as a secondary malignant neoplasm. Available data indicate that ALL often follows chemoradiotherapy for soft tissue sarcoma. Perivascular epithelioid tumor (PEComa), a primitive mesenchymal tissue origin, can be classified as a soft tissue sarcoma. An 11-year-old girl was diagnosed with ALL secondary to chemoradiotherapy (vincristine, ifosfamide, and anthracycline) and radiotherapy comprising 45 Gy to the whole pelvis for PEComa. ALL, FAB L2, and immunophenotypically pro-B developed 16 months after the final chemotherapy treatment. Moreover, a cytogenetic study of lymphoblasts showed t(1;11)(p32;q23). Herein, the authors report a case of secondary ALL that might be related to a previously used intercalating DNA topoisomerase II inhibitor (anthracycline) for a very rare sarcoma, PEComa.

Multimodal Treatment Using Surgery, Radiotherapy, and Chemotherapy in a Patient With a Perivascular Epithelioid Cell Tumor of the Uterus

Perivascular epithelioid tumor (PEComa), a recently defined tumor, is a very rare disease affecting various organs, most often the uterus. This tumor displays a variety of histologic and clinical features and at this point is regarded as a tumor with uncertain malignant potential. A 9-year-old girl with abdominal pain and vaginal spotting was diagnosed with PEComa of the uterus with metastasis. She received chemotherapy comprising vincristine, ifosfamide, and doxorubicin, as well as radiotherapy after surgery. After this multimodal treatment, there was no evidence of recurrence or further metastasis. She remains disease-free 1.5 years after her initial diagnosis. PEComa of the uterus displaying malignant characteristics may have a more favorable response to more aggressive therapy.

Perivascular epithelioid tumor of urinary bladder and vagina

Perivascular epithelioid cell tumors are recently characterized neoplasms composed of large clear HMB-45-positive epithelioid cells arranged in an organoid pattern. The histogenesis of these neoplasms remain obscure. We report here 2 such tumors in young female patients aged 19 and 16 years involving the urinary bladder and vagina, respectively (in the absence of the tuberous sclerosis complex) . Microscopically, both tumors were composed of perivascularly arranged cells with granular eosinophilic fluffy cytoplasm, round-to-oval nuclei, and prominent nucleoli. Melanin pigmentation was present in the vaginal tumor. Immunohistochemically, both tumors strongly expressed HMB-45. They were negative for cytokeratin, vimentin, and S-100. The vaginal tumor recurred 10 months after resection and chemotherapy. The patient with the bladder tumor was lost to follow-up.