Perivascular epithelioid cell tumor of the rib

Abstract

We present a rare case of perivascular epithelioid cell tumor (PEComa) in the right 6th rib of a 28-year-old man. A plain computed tomography scan showed a round osteolytic lesion in the right 6th rib. The resected tissue contained a globular-shaped, soft tumor. Histologically, the tumor was rich in vasculature and exclusively composed of perivascular epithelioid cells with clear cytoplasm. Immunohistochemically, the tumor expressed diffusely a melanocyte marker, human melanoma black-45, and focally a myogenic marker, alpha-smooth muscle actin, but not an epithelial marker, AE1/AE3. Fontana-Masson-positive melanin pigments were present and c-kit receptor tyrosine kinase (CD117), involved in the development of melanocytes but not myogenic cells, was expressed in tumor cells. These findings indicate that the tumor is PEComa with some differentiation into melanocytes. Notably, owing to the unique location of the occurrence, the tumor occupied bone marrow tissues of the rib, resulting that the tumor has the potential for hematogenous metastasis. In spite of the lack of cells with severe atypia, necrosis, and numerous mitoses, tumor cells invaded into surrounding tissues and overexpressed cyclin D1. To the best of our knowledge, this is the first case report of PEComa arising from the rib with the signs of malignant potential.

Malignant perivascular epithelioid cell tumour of the fibula: a report and a short review of bone perivascular epithelioid cell tumour

“…The right fibula was the site of involvement in two cases, the right tibia in one case and the sixth right rib in one case. In terms of histology, two cases were benign,4 5 one case exhibiting malignant potential in view of tumour invasion beyond the confines of the bone in association with overexpression of cyclin D16 and, in our case, a malignant neoplasm fulfilling the criteria proposed by Folpe et al 8. HMB-45 expression varied from focal to diffuse.…”

“…To date, a total of four cases (inclusive of the current case) of primary bone PEComa have been reported 4 – 6. A report of skull base PEComa was not included as a primary bone site, because the meninges might be the primary site 7.…”

“…Perivascular epithelioid cell tumour (PEComa) is a mesenchymal tumour composed of histologically and immunohistochemically distinctive PECs, encompassing angiomyolipoma, clear cell “sugar” tumour of the lung, lymphangioleiomyomatosis and a group of rare neoplasms that arise from the skin, soft tissue and visceral organs 2 3. A primary bone PEComa is uncommon, with only three previously reported cases in the English literature 4 – 6…”

Perivascular Epithelioid Cell Tumor of the Heart in a Child

“…The present tumor consisted predominantly of spindle cells. Occasional intranuclear pseudoinclusions and stromal calcifications were present, features only described previously in a small number of PEComas [7][8][9][10].…”

Diagnosis and treatment of malignant PEComa tumours

“…In a large analysis 24 pancreatic PEComa cases were presented, of which half were localised in the head of the pancreas [12] and numerous PEComas of the digestive tract [11,15], including the stomach [16], the ileus [17] and the colon [18]. Moreover, single cases in various locations have been described: the greater omentum [19], the gall bladder [20], the common bile duct [21], the breast [22], the thigh bone [6], rib [23], skull base [24], heart [25], pericardium [26], the prostate [27,28], ovary [29], nasal cavity [30], throat [31], eye socket [10], urinary bladder [32], lung [33], and the groin [34].…”