Primary perivascular epithelioid cell tumor (PEComa) in bone: A review of the literature and a case arising in the humerus with multiple metastases

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First case PEComa primary arising in humerus was described.

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Histology is the basic to determine malignancy of PEComa.

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TFE3 gene investigation is the key of therapy selection.

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mTOR inhibitor is believed to be effective for patients without TFE3 rearrangement.

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More study is needed to understand the role of molecular test and imaging in PEComa.

Introduction

Perivascular epithelioid cell tumors (PEComas) are a family of mesenchymal tumors that rarely arise as a primary bone tumor.

Material and methods

We report a case of primary malignant bone PEComa. A literature review via PubMed, Embase and Web of Science databases with the keyword “PEComa” and “bone” was performed.

Results

We reported a 33-year-old female with primary malignant bone PEComa in right distal humerus. The patient received an inhibitor of the mammalian target of rapamycin (mTOR) protein based on negative molecular investigation result of transcription factor E3 (TFE3) rearrangement, and additional therapies including palliative radiotherapy, anti-angiogenics and immunotherapy when the disease progression was detected. The patient was alive with the disease twenty-three months postoperatively. A total of nineteen related literature cases were retrieved and reviewed. Taking current case into account, ten males and ten females with median age of 24 years (range, 3–93 years) were identified, who were most frequently affected in tibia. The median follow-up duration of 24 months (range, 3–96 months). One patient died due to this disease, and six patients showed metastases. Three patients experienced recurrence, and two of them experienced twice and three times, respectively.

Conclusion

To our knowledge, this is the first case of primary malignant bone PEComa arising in humerus. Clinicopathological and radiological correlation is mandatory to the correct diagnosis and to determine its malignancy. More studies are required to understand the role of molecular test and imaging in selecting suitable treatment and mechanisms of treatment resistance.

S-100-Negative malignant pulmonary granular cell tumor: A case report

Malignant pulmonary granular cell tumor (GCT) is extremely rare and difficult to distinguish from benign GCT. Most GCTs are neural-type and express S-100. However, a small subset of tumors sub-classified as the non-neural type do not express S-100. We report a case of malignant non-neural-type GCT in the lungs.

A 77-year-old woman felt chest discomfort and dyspnea in July 2019. She had never smoked and had no medical history other than hypertension and diabetes mellitus.

She was initially evaluated at a local hospital. Flexible bronchoscopy showed total occlusion of the right main bronchus by a mass-like lesion. Biopsy of the mass lesion revealed chronic inflammation. The patient visited for re-evaluation in September 2019. Rigid bronchoscopy showed worsening of the total obstruction of the right main bronchus by a tumor mass, such that the carina was not visible. Additionally, endobronchial nodules were observed on the medial side of left main bronchus. The tumor masses of both main bronchi were removed by bronchoscopic intervention, but the right main bronchus was not opened. Biopsy revealed malignant GCT, favoring the non-neuronal type (S-100-negative).

We report an extremely rare case of malignant pulmonary GCT negative for S-100 in immunohistochemistry. In this case, surgical resection was not possible because the tumor was diagnosed at a fairly advanced stage and had spread to involve the contralateral main bronchus. The patient chose to be treated at another hospital and was thereafter lost to follow-up.

Pneumothorax caused by cystic and nodular lung metastases from a malignant uterine perivascular epithelioid cell tumor (PEComa)

Perivascular epithelioid cell tumors (PEComas) are mesenchymal neoplasms with immunoreactivity for both melanocytic and smooth muscle markers. PEComas occur at multiple sites, and malignant PEComas can undergo metastasis, recurrence and aggressive clinical courses. Although the lung is a common metastatic site of PEComas, they usually appear as multiple nodules but rarely become cystic or cavitary. Here, we describe a female patient whose lungs manifested multiple cystic, cavity-like and nodular metastases 3 years after the resection of uterine tumors tentatively diagnosed as epithelioid smooth muscle tumors with uncertain malignant potential. This patient's subsequent pneumothorax necessitated video-assisted thoracoscopic surgery, and examination of her resected lung specimens eventually led to correcting the diagnosis, i.e., to a PEComa harboring tuberous sclerosis complex 1 (TSC1) loss-of-heterozygosity that originated in the uterus and then metastasized to the lungs. The administration of a gonadotropin-releasing hormone analogue later stabilized her clinical course. To the best of our knowledge, the present case is the first in the literature that associates PEComas with a TSC1 abnormality. Additionally, the pulmonary manifestations, including imaging appearance and pneumothorax, somewhat resembled those of lymphangioleiomyomatosis, a representative disease belonging to the PEComa family. Although PEComas are rare, clinicians, radiologists and pathologists should become aware of this disease entity, especially in the combined clinical setting of multiple cystic, cavity-like, nodular lesions on computed tomography of the chest and a past history of the tumor in the female reproductive system.

Leiomyosarcoma of the urinary bladder: A review and a report of two further cases

OBJECTIVES

To review the published cases of leiomyosarcoma of the urinary bladder and to report two further cases.

METHODS

The databases Pubmed and Hinari were searched using the keywords 'bladder', 'leiomyosarcoma' and 'smooth muscle neoplasm'. The 14 articles identified were reviewed, and we present a further two cases.

RESULTS

Of more than 100 cases reported, 77 were reviewed. There is a lack of consensus about the standard treatment, and little is known about the natural history and prognosis of the tumour, due to its very low incidence. These tumours occur in older adults of either sex and are characterised by an aggressive behaviour. There is usually an unfavourable outcome, with the lungs being the most common site of metastasis. The two further cases we report had a different presentation and outcome.

CONCLUSIONS

Because of the limited experience with this rare tumour, there are insufficient data to suggest the optimum management strategy and prognosis.