Malignant perivascular epithelioid cell tumor of the oropharynx with strong TFE3 expression mimicking alveolar soft part sarcoma: a case report and review of the literature

Exploring perivascular epithelioid cell tumors (PEComas) in the CNS: insights from two case reports and a comprehensive literature review

Perivascular epithelioid cell tumors (PEComas) represent a rare and intriguing subset of neoplasms within the central nervous system (CNS). This report describes two unique cases that highlight distinct origins and clinical behaviors, offering valuable contributions to the limited body of knowledge regarding CNS PEComas. Despite their rarity, PEComas should be considered in the differential diagnosis of mesenchymal tumors that display an atypical combination of clinical, radiological, and histomolecular features, especially when melanocytic and/or myoid markers are present. Treatment with mTOR inhibitors can potentially stabilize the disease in a significant number of more aggressive PEComas, even those located in the CNS.

TFE3 -rearranged Head and Neck Neoplasms : Twenty-two Cases Spanning the Morphologic Continuum Between Alveolar Soft Part Sarcoma and PEComa and Highlighting Genotypic Diversity

TFE3 rearrangements characterize histogenetically, topographically, and biologically diverse neoplasms. Besides being a universal defining feature in alveolar soft part sarcoma (ASPS) and clear cell stromal tumor of the lung, TFE3 fusions have been reported in subsets of renal cell carcinoma, perivascular epithelioid cell tumor (PEComa), epithelioid hemangioendothelioma and ossifying fibromyxoid tumors. TFE3 -related neoplasms are rare in the head and neck and may pose diagnostic challenges. We herein describe 22 TFE3 fusion neoplasms affecting 11 males and 11 females aged 4 to 79 years (median, 25) and involving different head and neck sites: sinonasal cavities (n = 8), tongue (n = 4), oral cavity/oropharynx (n = 3), salivary glands (n = 2), orbit (n = 2), and soft tissue or unspecified sites (n = 3). Based on morphology and myomelanocytic immunophenotype, 10 tumors qualified as ASPS, 7 as PEComas (3 melanotic; all sinonasal), and 5 showed intermediate (indeterminate) histology overlapping with ASPS and PEComa. Immunohistochemistry for TFE3 was homogeneously strongly positive in all cases. Targeted RNA sequencing/FISH testing confirmed TFE3 fusions in 14 of 16 successfully tested cases (88%). ASPSCR1 was the most frequent fusion partner in ASPS (4 of 5 cases); one ASPS had a rare VCP::TFE3 fusion. The 6 successfully tested PEComas had known fusion partners as reported in renal cell carcinoma and PEComas ( NONO, PRCC, SFPQ , and PSPC1 ). The indeterminate tumors harbored ASPSCR1::TFE3 (n = 2) and U2AF2::TFE3 (n = 1) fusions, respectively. This large series devoted to TFE3-positive head and neck tumors illustrates the recently proposed morphologic overlap in the spectrum of TFE3 -associated mesenchymal neoplasms. While all PEComas were sinonasal, ASPS was never sinonasal and occurred in diverse head and neck sites with a predilection for the tongue. The indeterminate (PEComa-like) category is molecularly more akin to ASPS but shows different age, sex, and anatomic distribution compared with classic ASPS. We report VCP as a novel fusion partner in ASPS and PSPC1 as a novel TFE3 fusion partner in PEComa (detected in one PEComa). Future studies should shed light on the most appropriate terminological subtyping of these highly overlapping tumors.

TFE3-rearranged perivascular epithelioid cell tumors of the head and neck with rare fusion partners: clues to the differential diagnosis between benign and malignant tumors

BACKGROUND

Perivascular epithelioid cell tumors (PEComas) rarely appear in the head and neck region. This case report describes two transcription factor E3 (TFE3)-rearranged PEComa cases, consisting of one in the orbit and one in the nasal cavity.

CASE PRESENTATION

Both cases demonstrated sheet-like or focal nested architecture and comprised epithelioid cells with abundant clear to eosinophilic cytoplasm and vascular stroma. The first case exhibited partial pleomorphism, a small necrosis area, and slightly increased mitosis and was classified as malignant. The second case demonstrated mild atypia and no mitosis or necrosis and was categorized as benign. The nasal tumor was initially considered a TFE3-rearranged renal cell carcinoma metastasis. However, a subsequent renal tumor biopsy revealed angiomyolipoma. The RNA sequence revealed ZC3H4::TFE3 and PRCC::TFE3 fusions in the first and second cases, respectively.

CONCLUSION

The fusion partner gene ZC3H4 is uncommon, and this is the third reported PEComa case. The fusion partner gene PRCC is often reported in TFE3-rearranged renal cell carcinoma, and this PEComa case is the second reported in the head and neck region. The initially reported cases with the fusion partner genes ZC3H4 and PRCC were categorized as malignant. These cases were discussed with a literature review.

An unusual case of primary splenic soft part alveolar sarcoma: case report and review of the literature with emphasis on the spectrum of TFE3-associated neoplasms

BACKGROUND

Alveolar soft part sarcoma is a rare tumour of soft tissues, mostly localized in muscles or deep soft tissues of the extremities. In rare occasions, this tumour develops in deep tissues of the abdomen or pelvis.

CASE PRESENTATION

In this case report, we described the case of a 46 year old man who developed a primary splenic alveolar soft part sarcoma. The tumour displayed typical morphological alveolar aspect, as well as immunohistochemical profile notably TFE3 nuclear staining. Detection of ASPSCR1 Exon 7::TFE3 Exon 6 fusion transcript in molecular biology and TFE3 rearrangement in FISH confirmed the diagnosis.

CONCLUSION

We described the first case of primary splenic alveolar soft part sarcoma, which questions once again the cell of origin of this rare tumour.

Case Report: Perivascular epithelioid tumors of the gastrointestinal tract

Background

Perivascular epithelioid cell tumor of the gastrointestinal tract (GI PEComa) is a rare mesenchymal neoplasm. GI PEComa is mostly observed in the colon and has a marked middle-aged female predominance. PEComa has no typical clinical or imaging manifestations or endoscopic characteristics. Therefore, the diagnosis of this disease mostly relies on pathological findings. HMB-45 is a sensitive immune marker of PEComa.

Case presentation

We reported a case of a middle-aged female with sigmoid colon PEComa. To exclude carcinogenesis, the large basal polyp in the sigmoid colon was removed by endoscopic mucosal resection (EMR). Immunohistochemistry analysis results showed that this lesion expressed HMB-45, which is a characteristic melanin marker of PEComa. Finally, the lesion was diagnosed as sigmoid colon PEComa. At the time of submission of this report, surgical resection was the primary treatment for PEComa. Though the characteristics of tumor biology and clinical behavior in PEComa are not clear, the boundary is clear, and the tumor can be completely removed. However, close follow-up is required after the surgery because of the lesion's undetermined benign and malignant nature.

Conclusion

The present case study emphasizes the importance of pathological diagnosis. Therefore, upon finding gastrointestinal polyps with a mucosal ulcer under endoscopy, the GI PEComa diagnosis should be considered. It is necessary to detect the characteristic melanin markers of PEComa. Due to the rarity of these cases, challenges are faced in diagnosing and treating PEComa.

Advancements in the diagnosis and treatment of renal epithelioid angiomyolipoma: A narrative review

Renal epithelioid angiomyolipoma (EAML) is a unique subtype of angiomyolipoma that contains a variety of cytoplasmic-rich, eosinophilic cytoplasm epithelioid cells in addition to mature adipocytes, hyaline thick-walled vessels, and smooth muscle-like spindle cells. In recent years, increasing evidence has shown that EAML is a potentially malignant tumor. Due to the lack of typical clinical manifestations and imaging features, it is difficult to diagnose before surgery, and the diagnosis mainly depends on postoperative histopathological examination. With the advancement of pathological diagnostic techniques, more EAML cases has been discovered, but clinicians still lack a comprehensive understanding of EAML. This review comprehensively describes some pathological and clinical features of EAML, with special attention to the pathogenesis and treatment of malignant EAML in order to assist with clinical diagnosis and treatment.

The current management of alveolar soft part sarcomas

OBJECTIVE

Alveolar soft part sarcomas (ASPS) which has high potential ability of metastasis, is a rare and slowly growing malignant tumor, and mainly primary localized in limbs. To date, little is known about the best treatment of ASPS. This study aims to review the current management and advance of ASPS.

METHODS

WANFANG MED ONLINE, CNKI, and NCBI PUBMED were used to search literature spanning from 1963 to 2020, and all cases of ASPS about "ASPS, diagnosis, treatment, surgery, radiotherapy, chemotherapy, target therapy or immune therapy" with detailed data were included.

RESULTS

Complete surgical resection remained the standard management strategy, radiotherapy was reported to be used for the patients of micro- or macroscopical incomplete residue or the surgical margin was questionable. Chemotherapy was controversial. Some target drugs and immune checkpoint inhibitors had produced antitumor activity.

CONCLUSION

Complete surgical resection is the cure treatment for ASPS, and adjuvant chemotherapy is not recommended excepted clinical trials. For the patients with micro- or macroscopical incomplete residue, radiotherapy should be appreciated. Furthermore, for recurrence, distant metastasis, and refractory of ASPS, combination therapy, especially combination with multiple target agents and/or immune checkpoint inhibitors may prolong survival time.

Alveolar soft part sarcoma presenting in an unusual laryngeal location

Alveolar soft part sarcoma (ASPS) is a rare malignant neoplasm that tends to occur in the deep soft tissues of both adults and children. ASPS has a progressive clinical course that is unfortunately characterised by late metastases and an overall poor prognosis. Although the tumour has been reported in a wide range of anatomic sites, few cases of primary laryngeal ASPS are reported in the literature. Here, we report the case of a 24-year-old man with no significant medical history who presented with progressive mild dysphonia and hoarseness. Imaging studies revealed a well-circumscribed, partially cystic submucosal mass with involvement of the right vocal fold and other local structures, and the patient was referred for surgical excision. Morphological and immunohistochemical examination of the excised lesion revealed ASPS. The findings of this case are compared with those of seven additional cases of primary laryngeal ASPS, which were found following literature review.

Case Report: Gastrointestinal PEComa With TFE3 Rearrangement Treated With Anti-VEGFR TKI Apatinib

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors. Unresectable malignant PEComas with TFE3 rearrangement have no recommended therapy to date. Here, we report the first case of malignant gastrointestinal PEComa with TFE3 rearrangement which has a response to the targeted therapy of an anti-VEGFR tyrosine kinase inhibitor (TKI), apatinib. A 31-year-old female was diagnosed with malignant gastrointestinal PEComa with TFE3 rearrangement and hepatic metastases. A resection of the giant retroperitoneal mass was performed. The patient received the anti-VEGFR TKI apatinib to treat the hepatic metastasis. The tumor remained stable during apatinib treatment and the progression-free survival (PFS) lasted about 7 months. This case suggests that targeting the VEGF/VEGFR signaling pathway may be an essential new therapeutic choice for TFE3-associated malignant PEComas.

Perivascular epithelioid cell tumor (PEComa) of the pterygopalatine fossa

Perivascular epithelioid cell tumors (PEComas) are a rare group of mesenchymal tumors associated with tuberous sclerosis. These tumors are typically treated with resection and rarely recur or exhibit malignant behavior. A 78-year-old woman presented with an incidentally discovered pterygopalatine fossa/retroantral mass. Excisional biopsy was performed and revealed pathology consistent with PEComa. Upon review of the literature, there have been 43 reported cases of PEComa of the head and neck. There is only one previously reported case of PEComa in the skull base, and none reported in the pterygopalatine fossa. Of note, the previously reported case of skull base PEComa involved an aggressive tumor with widespread metastasis. Here, we report the first case of a PEComa of the pterygopalatine fossa/retroantral region, which was treated conservatively. This rare pathology should be considered in the differential diagnosis for atypical skull base tumors.

Malignant perivascular epithelioid cell tumor mimicking jugular foramen schwannoma: A case report and literature review

Background

Perivascular epithelioid cell tumors (PEComas) of the skull base are extremely rare. Here we report the first description of a malignant PEComa mimicking jugular foramen schwannoma and presenting as Collet-Sicard syndrome, and we review the previous literature on PEComas of the head, neck and skull base.

Case description

A 29-year-old woman presented with hoarseness, dysphagia, vomiting, and headache. She was first diagnosed with Collet-Sicard syndrome caused by thrombosis of the sigmoid and transverse sinuses. She was treated with anticoagulant therapy, and the hoarseness and paralysis of the accessory nerve improved. Later, at age 31, the hoarseness again worsened. At another hospital, enhanced computed tomography revealed a tumor in the jugular foramen extending to the neck and medially displacing the internal carotid artery. She was referred to our hospital for further examination and was diagnosed with jugular foramen schwannoma causing thrombosis of the sinuses. At the one-year follow-up, the tumor had grown rapidly and had started to surround the internal carotid artery. We therefore performed a tissue biopsy of the tumor in the jugular foramen and neck. Based on pathological analysis, we made a definitive diagnosis of malignant PEComa.

Conclusions

It may be extremely challenging to reach an accurate diagnosis of PEComa in the skull-base region, which can cause a delay in treatment initiation. When atypical clinical features for a skull-base tumor are found, we recommend preliminary biopsy to obtain a definitive diagnosis and initiate an appropriate treatment strategy as early as possible.

Bladder PEComa: A case report and literature review

The location of PEComa is rare in bladder, and the misdiagnosis rate is very high before operation.the characteristic of the bladder PEComa is that the CT is a round, elliptical or irregular cystic mass with a large volume, more than 5 cm or more, and the edge is clear. The solid part of the scanning tumor is obviously enhanced, and the rich blood supply artery and the drainage vein can be seen.