Perivascular epithelioid cell tumors (PEComas) of the head and neck: report of three cases and review of the literature

Unusual PEComa With PRCC :: TFE3 Fusion Mimicking Sinonasal Tract Melanoma

BACKGROUND

We report a nasal cavity unusual perivascular epithelioid cell tumor (PEComa) mimicking mucosal melanoma.

METHODS

Immunohistochemistry was performed using BenchMark Ultra and panel of antibodies. The Ion Torrent platform and Ion AmpliSeq cancer hotspot panel were utilized for DNA genotyping. Target-specific RNA libraries for the detection of fusion transcripts were constructed using Archer Universal RNA Reagent Kit v2 and Archer FusionPlex Solid Tumor panel and sequenced on the MiSeqDx instrument.

RESULTS

The tumor, diagnosed in 46-year-old female, was composed of spindle cells, and lacked pigmentation. Immunohistochemically, it showed a patchy HMB-45 positivity. Other melanocytic markers (S100 protein, Melan-A, SOX10) were negative. The tumor cells were weakly positive for KIT (CD117) while negative for smooth muscle actin, pancytokeratin cocktail (AE1/AE3), and synaptophysin. Diagnosis of primary sinonasal tract mucosal melanoma was favored. Additional molecular studies detected PRCC :: TFE3 fusion as the sole genetic change, and suggested the diagnosis of unusual PEComa. Previously, TFE3 fusions were reported in a subset of PEComas but not in melanomas, while PRCC involvement has only been documented once in an ocular PEComa. Immunohistochemistry revealed strong nuclear TFE3 expression concordant with the molecular findings.

CONCLUSIONS

This report emphasis the importance of molecular testing in the differential diagnosis between PEComa and melanoma, especially when the tumor arises in a site typical of melanoma but showing an unusual morphology and immunophenotype. The detection of TFE3 fusion transcripts suggested the diagnosis of SNT PEComa, although it cannot be excluded that this and similar tumors represent a distinct diagnostic category.

Perivascular epithelioid cell tumor of the lacrimal gland

A 33-year-old lady was referred to our clinic with a history of left upper eyelid swelling and difficulty to open her left eye for more than 4 years. Her globe was in infero-nasal displacement, and ocular movement was not full, with restriction to every direction. No clinical sign including eye redness, pain or visual loss was found on examination. Exophthalmometry confirmed 2 mm of left-sided proptosis. Computed tomography (CT) imaging of the orbit obtained in axial and coronal planes depicted an irregular and heterogeneous soft-tissue density mass in the left lacrimal gland, measuring 25 × 17 mm. Magnetic resonance imaging (MRI) revealed the mass of slightly longer T1 and slightly longer/shorter T2 signal, and Gd-enhanced MRI showed a significant enhancement. The tumor was first presumably diagnosed of pleomorphic adenomas. A surgery was applied to remove the tumor completely. Histopathological evaluation led to the diagnosis of PEComa.

A rare case of a laryngeal angiomyolipoma

Laryngeal angiomyolipoma is a rare tumor with few reported cases in the literature. The case report explains a 62-year-old man who presents with dyspnea and found to have a laryngeal angiomyolipoma staining CD34 positive, but HMB45 and Melan-A negative.

Perivascular epithelioid cell tumour-mimicking retroperitoneal leiomyosarcoma

A young man in his 40s was evaluated in the emergency department for abdominal and right flank pain. A CT scan of the abdomen and pelvis showed a solid, well-circumscribed lesion measuring 7.1×8.1×5.4 cm, which was arising from the retroperitoneum and extending from the third portion of the duodenum towards the right kidney. A percutaneous core biopsy was obtained, demonstrating an atypical smooth muscle neoplasm suggestive of a low-grade leiomyosarcoma. The patient underwent surgery for an en-block resection of the mass and the final pathology confirmed a perivascular epithelioid cell neoplasm without significant pleomorphism, mitosis or necrosis. Our case adds to the small number of perivascular epithelioid cell tumour cases reported in the literature and we present it in order to increase our understanding of this tumour and to assist in its appropriate diagnosis and management.

Rare case of angiomyolipoma of the larynx

We report a rare case of angiomyolipoma (AML) of the larynx. AML belongs to the family of perivascular epithelioid cell tumors (PEComas). We review the literature on PEComas and describe differences in immunohistochemical findings between renal AML and AML in the head and neck region.

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.

Nasal Angiomyolipoma (AML) Mimicking Juvenile Nasopharyngeal Angiofibroma

INTRODUCTION

Angiomyolipoma (AML), a benign mesenchymal tumor that commonly arises from the kidney, may be associated with tuberous sclerosis complex and perivascular epithelioid cell tumors (PEComas). Nasal angiomyolipoma is very rare and usually occurs in elderly individuals with epistaxis and nasal obstruction.

CASE REPORT

We report a rare case of nasal angiomyolipoma in a young male. To the best of our knowledge, this is the first documented case of angiomyolipoma originating from the posterior end of the inferior turbinate, clinically mimicking juvenile nasopharyngeal angiofibroma (JNA). The tumor was removed completely via coblator-assisted endoscopic sinus surgery. The patient was asymptomatic at a 2-year follow-up.

CONCLUSION

Nasal AML located in the posterior nasal cavity in a male patient can mimic the presentation of JNA. A computed tomography scan of the paranasal sinuses played an important role in differentiating nasal AML from JNA. The coblator-assisted endoscopic technique is useful in controlling intraoperative hemostasis in the removal of a suspicious vascular tumor.

Giant Perivascular Epithelioid Cell Tumor of the Orbit: A Clinicopathological Analysis and Review of the Literature

Aim

To describe and review the clinical, radiological, and histopathological characteristics of an orbital perivascular epithelioid cell tumor (PEComa).

Methods

A systematic review of clinical records, radiological investigations, microscopic features, and immunohistochemical characteristics was done.

Results

A 9-year-old female child presented with a year-long history of a large orbital mass associated with painless, progressive proptosis of the right eye. Radiologically, a well-defined orbital mass was seen with no intracranial extension. Excision was performed and histopathological examination showed uniform epithelioid cells in nests separated by thin fibrovascular septae. The tumor cells stained positively for Human Melanoma Black-45, but neg-atively for desmin, S-100, smooth muscle actin, MyoD1, microphthalmia-associated transcription factor, vimentin, CD10, CD31, and CD34 with a low proliferation index of 5-7%. Based on the tumor's morphological and immuno-histochemical characteristics, a diagnosis of giant orbital PEComa was made. No recurrence was seen at the last follow-up.

Conclusions

PEComas are uncommon mesenchymal neoplasms that have typical histological features, with an immunohistochemical profile of negativity for epithelial markers and positivity for melanocytic markers. For benign PEComas, complete excision is advised. However, since PEComas elsewhere in the body have been known to be malignant, a close follow-up of such cases is recommended.

An orbital perivascular epithelioid cell tumor in a 7-year-old boy: case report and review of the literature

We report the case of a 7-year-old boy who presented with a swollen right eye. Magnetic resonance imaging revealed a right intraconal orbital mass with intense contrast enhancement. Incisional biopsy led to a diagnosis of perivascular epithelioid cell tumor (PEComa). Sirolimus was initiated but discontinued at the third week of treatment because the tumor had progressed. A minor regression of the tumor was seen after six cycles of systemic chemotherapy. Previously reported cases of PEComa were benign in nature, and full remission was achieved with surgical excision. In the present case the tumor was malignant and responded only slightly to systemic chemotherapy.

Melanotic PEComa of the Sinonasal Mucosa With NONO-TFE3 Fusion: An Elusive Mimic of Sinonasal Melanoma

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal tumors with features of both smooth muscle and melanocytic differentiation, with or without true melanin pigment. The highly variable morphology of PEComas results in a broad differential diagnosis that is also dependent on anatomic site. A subset demonstrates rearrangements involving the TFE3 (Xp11) locus, which can be used in diagnostically difficult cases. Here we describe a case of a melanotic PEComa with NONO-TFE3 fusion occurring in the sinonasal mucosa, as demonstrated by both next-generation sequencing and molecular cytogenetic studies. This case is the first of its kind in the literature and only the second documented PEComa harboring a NONO-TFE3 rearrangement. In light of unequivocal molecular ancillary studies, this case illustrates that PEComa must enter the differential for pigmented lesions of the sinonasal mucosa, where malignant melanoma would be much more likely to occur.

S-100 Negative Granular Cell Tumor (So-called Primitive Polypoid Non-neural Granular Cell Tumor) of the Oral Cavity

Four cases of cutaneous S-100 negative granular cell tumor were described in 1991. Until now, only 3 cases of oral involvement have been documented in English literature. Two additional cases of oral S-100 negative granular cell tumor are described. Immunohistochemical markers were applied to exclude other lesions that may show the presence of granular cells. The clinical findings were correlated with the histopathological and immunohistochemical features to arrive at the appropriate diagnosis. S-100 negative granular cell tumors are erythematous polypoid masses commonly mistaken for granulation tissue or a pyogenic granuloma. Any part of the oral cavity may be affected. Histopathologically, the lesions consist of sheets, nests, and fascicles of granular cells that are S-100 negative. The granular cells are non-reactive to SMA, HMB45, Melan A, and CD163. The intracytoplasmic granules are diffusely and strongly positive to NKI/C3. The cell lineage of the S-100 negative granular cell tumor is obscure. Absence of staining with CD163 excludes a histiocytic lineage. Absence of staining with S-100 excludes a neural origin. Absence of staining with S-100 and key melanoma markers HMB45 and Melan A also excludes a melanocytic origin. In this context, positive reactivity with NKI/C3 is indicative of presence of intracytoplasmic lysosomal granules only. Greater awareness of this lesion in the oral cavity will result in better characterization of its biologic potential.

Pigmented perivascular epithelioid cell tumor of the skin: first case report

The authors present a first case of pigmented perivascular epithelioid cell tumor (PEComa) of the skin, which was misdiagnosed histopathologically as metastatic melanoma. PEComa are exceedingly rare neoplasms, and only a few cases have been reported in kidney, liver, and pelvis. Herein, we describe this very rare entity in the subcutaneous tissue of the flank with very similar if not identical morphology of renal clear cell carcinoma. Because of the presence of focal melanin pigmentation and strong positivity for HMB-45, the lesion was mistaken for metastatic melanoma. To the best of authors' knowledge, this is the first case of cutaneous PEComa with melanin pigmentation. Awareness about occurrence of the lesion in the subcutaneous tissue and its unique immunoprofile would be helpful to reach correct diagnosis and to distinguish this lesion from melanoma or metastatic renal clear cell carcinoma.

Primary clear cell sarcoma of the head and neck: a case series with review of the literature

BACKGROUND

Clear cell sarcoma typically arises in deep soft tissues of the foot/ankle. Primary head and neck clear cell sarcoma is rare. We report three molecularly confirmed primary head and neck clear cell sarcoma and review the literature.

METHODS

Head and neck clear cell sarcoma with no primary elsewhere were retrieved from archival/consultation files. English language literature review of all reported head and neck clear cell sarcoma was performed.

RESULTS

Three cases were identified. The tumors, all in men, presented on the scalp of a 33-year-old, face of a 20-year-old and tongue of a 44-year-old. Tumors ranged from 0.6 to 1.4 cm. All had typical features of clear cell sarcoma, including nests of tumor cells divided by fibrous septae. One had multinucleated wreath-like giant cells. One had a focal junctional component. Immunohistochemistry was positive for S100 (three out of three), HMB45 (three out of three) and Melan-A (two out of three). All had EWSR1 rearrangements by fluorescence in situ hybridization. Follow up available for one patient revealed no evidence of disease after wide excision and radiation. Seven additional reported cases were identified and tabulated.

CONCLUSION

Head and neck clear cell sarcoma is rare but should be considered in the differential diagnosis of nested tumors with fibrous septae. Molecular analysis should be considered for definitive diagnosis regardless of location.

Cutaneous PEComa: a rare entity to consider in an unusual site

PEComa is a mesenchymal neoplasm thought to derive from the perivascular epithelioid cell, a hypothetical cell type not yet identified. PEComa is a broad term that was recently expanded to include visceral, retroperitoneal, and somatic soft tissue, in addition to cutaneous tumors, which share morphological and immunohistochemical features in common with angiomyolipoma, lymphangiomyomatosis, and clear cell "sugar" tumor. The latter have distinct, site-related, clinical, morphological, and biological features. PEComas share features of concurrent melanocytic and myocytic differentiation. Most cases are sporadic, but renal and pulmonary PEComas can be part of the tuberous sclerosis syndrome more often than PEComas from other sites. We report a case of cutaneous PEComa to raise awareness of the entity occurring at this site and caution against misinterpretation as a primary or metastatic malignancy, for example melanoma or renal cell carcinoma, clear cell type.

PEComa of the nasal cavity with worrisome histologic features and benign behavior: a case report

OBJECTIVES

PEComas (perivascular epithelioid cell tumors) are a family of neoplastic lesions that share overlapping ultrastructure and morphological and immunohistochemical appearance and include angiomyolipoma, lymphangioleiomyomatosis, and clear cell "sugar" tumor of the lung, as well as similar tumors that occur in a variety of visceral, cutaneous, and soft tissue sites throughout the body.

METHODS

A 40-year-old woman came to medical attention because of epistaxis and because of unilateral nasal obstruction of 3 months' duration. Endoscopic examination revealed a well-demarcated exophytic lesion attached to the anterior portion of the middle turbinate.

RESULTS

The lesion was superficially located, and therefore amenable to complete surgical excision. Seven years after surgery, the patient is alive and well, without evidence of local recurrence or metastastic disease. Based on morphological and immunohistochemical appearance, a diagnosis of PEComa with worrisome histologic features was rendered.

CONCLUSIONS

In the present study, we describe a PEComa that occurred in the nasal cavity and discuss the behavior of this entity. The importance of recognizing this disease will ensure its consideration in the differential diagnosis of tumors of the head that have similar morphological features. The histogenesis of PEComa still remains elusive, and collection of additional cases with a prolonged follow-up will be important in accurately determining the behavior of these distinctive tumors.

Paragangliomas: update on differential diagnostic considerations, composite tumors, and recent genetic developments

Recent developments in molecular genetics have expanded the spectrum of disorders associated with pheochromocytomas (PCCs) and extra-adrenal paragangliomas (PGLs) and have increased the roles of pathologists in helping to guide patient care. At least 30% of these tumors are now known to be hereditary, and germline mutations of at least 10 genes are known to cause the tumors to develop. Genotype-phenotype correlations have been identified, including differences in tumor distribution, catecholamine production, and risk of metastasis, and types of tumors not previously associated with PCC/PGL are now considered in the spectrum of hereditary disease. Important new findings are that mutations of succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD, and SDHAF2 (collectively "SDHx") are responsible for a large percentage of hereditary PCC/PGL and that SDHB mutations are strongly correlated with extra-adrenal tumor location, metastasis, and poor prognosis. Further, gastrointestinal stromal tumors and renal tumors are now associated with SDHx mutations. A PCC or PGL caused by any of the hereditary susceptibility genes can present as a solitary, apparently sporadic, tumor, and substantial numbers of patients presenting with apparently sporadic tumors harbor occult germline mutations of susceptibility genes. Current roles of pathologists are differential diagnosis of primary tumors and metastases, identification of clues to occult hereditary disease, and triaging of patients for optimal genetic testing by immunohistochemical staining of tumor tissue for the loss of SDHB and SDHA protein. Diagnostic pitfalls are posed by morphological variants of PCC/PGL, unusual anatomic sites of occurrence, and coexisting neuroendocrine tumors of other types in some hereditary syndromes. These pitfalls can be avoided by judicious use of appropriate immunohistochemical stains. Aside from loss of staining for SDHB, criteria for predicting risk of metastasis are still controversial, and "malignancy" is diagnosed only after metastases have occurred. All PCCs/PGLs are considered to pose some risk of metastasis, and long-term follow-up is advised.

PEComa of the nose: report of a case with immunohistochemical and ultrustructural studies and a review of the literature

PEComas are a family of mesenchymal neoplasms that have in common the presence of a unique cell type, the perivascular epithelioid cell (PEC). PECs uniquely exhibit a distinct immunophenotype with expression of both melanocytic, particularly HMB-45, and myogenic markers. Nasal PEComas are exceedingly rare. To date, 14 cases have been described in the literature and with the exception of 6 cases, the rest consistently lack epithelioid cells and HMB-45 expression and are best classified as nasal hamartomas or angioleiomyomas with an adipocytic component. Nasal PEComas may closely resemble malignant melanomas since both entities share many morphologic, immunohistochemical, ultrastructural and clinical features. The distinction is of paramount importance as melanomas tend to display an aggressive behaviour with associated poor outcome. Herein, we report a case of nasal PEComa in a 19 year girl, focusing on the importance of light microscopic, immunohistochemical and ultrastructural features in accurately establishing the diagnosis.

Angiomyolipoma of the kidney: clinicopathological and immunohistochemical study

OVERVIEW

Although angiomyolipoma (AML) is a relatively rare entity, it is the most common benign mesenchymal neoplasm of the kidney.

THE AIM OF THIS STUDY

To highlight the clinicopathological characteristics of AML and to assess the role of Human Melanoma Black-45 (HMB-45), Melan-A, smooth muscle actin (SMA), S-100 and cytokeratin in its diagnosis.

MATERIALS AND METHODS

The study included 15 cases of AML. Clinical and radiological data were retrieved from the archival files and all cases were subjected to a histopathological evaluation as well as immunohistochemical staining for HMB-45, Melan-A, SMA, S-100, and cytokeratin.

RESULTS

AML was more common in females (female:male = 4:1), the mean age was 53.9 ± 6.45 years. 60% of patients were symptomatic while the remaining 40% were asymptomatic. A statistically significant relationship was found between size of the tumor and the presence of the symptoms (P = 0.02). Patients with tumor size less than 4 cm were asymptomatic, while those with tumor size larger than 4 cm had different symptoms. Thirteen cases were classic AML, while 2 cases were epithelioid AML. Classic AML demonstrated admixture of fatty tissue, thick-walled blood vessels, and smooth muscle, while epithelioid AML was composed mainly of epithelioid cells and contained no fat. HMB-45 was positive in all cases of AML (100%), Melan-A was positive in 13/15 (87%) while SMA was positive in 11/15 (73%) of AML with variable staining intensity. All cases of AML were negative for S-100 and cytokeratin.

CONCLUSION

AMLs have characteristic clinicopathological and immunohistochemical features and their recognition is crucial for proper diagnosis and treatment.

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.

A case of angiomyolipoma rarely located in the larynx

Angiomyolipoma is a rare benign mesenchymal tumor, which is mostly renal in origin. A sixty-year-old male patient with the diagnosis of angiomyolipoma located in the larynx has been presented here, and the literature is reviewed.