Search

This study describes the clinical, histologic, and immunohistochemical features of four cases of GI PEComa. The size of the tumors ranged from 3.5 to 6.0cm in diameter, and all were located in wall of the large bowel. Microscopically, the tumors were characterized by an epithelioid arrangement of tumor cells, which had abundant clear to pale eosinophilic granular cytoplasm, vesicular nuclei and prominent nucleoli. The stroma was rich in capillaries, a sinusoidal vasculature and thick-walled blood vessels. Mitotic figures were generally rare. Immunohistochemically, the tumors were positive for Vimentin (4/4), HMB-45 (4/4), Melan-A(4/4),alpha-smooth muscle actin (4/4), and desmin (3/4). The patients have been well with no evidence of disease at 8, 15, 32 and 36 months,respectively, after the surgical operation. GI tract PEComas should be regarded as tumors of an uncertain malignant potential until long-term outcome data for a larger number of patients become available. [ABSTRACT FROM AUTHOR]

Abstract: Perivascular epithelioid cell tumor (PEComa) of the laryngopharynx is extremely rare, and no such descriptions have been reported in the literature. This study describes the clinical, histological, and immunohistochemical features of three cases of laryngopharynx PEComa. The patients (two males and one female) were 38, 42, and 47 years old, respectively. Their tumors were well-demarcated, gray white on the cut surface with focal hemorrhage, and ranged from 3.0 to 5.0cm in diameter. Microscopically, the tumors were characterized by an epithelioid arrangement of tumor cells, which had abundant clear to pale eosinophilic granular cytoplasm, vesicular nuclei, and prominent nucleoli. The stroma was rich in capillaries, sinusoidal vasculature, and thick-walled blood vessels. Mitotic figures were rare. The tumors showed no cellular atypia, with two of them having moderate atypical nuclei focally. Immunohistochemically, the tumor cells were diffusely or focally positive for vimentin (3/3), HMB-45 (3/3), melan-A(3/3), alpha-smooth muscle actin (3/3), and S-100(1/3). They were uniformly negative for CK, Syn, CgA, CD34, CD10, and CD117. Two patients are well, with no evidence of disease at 13 and 30 months after surgery, one patient had recurrence at 15 months after operation. Laryngopharynx PEComas should be regarded as tumors with a malignant potential. [Copyright &y& Elsevier]