Murine macrophages cultured with IL-4 acquire a phenotype similar to that of epithelioid cells from granulomatous inflammation.

Epithelioid cells (ECs) found in granulomas are thought to derive from mononuclear phagocytes. Although GM-CSF and/or IL-4 are known to promote cell differentiation their role in the development of ECs has never been demonstrated. Here we showed that mouse macrophages treated exclusively with recombinant IL-4 (rIL-4) differentiate into epithelioid-like cells. Macrophages cultivated with rIL-4 presented a fried-egg shape, and ultrastructural studies revealed membrane interdigitations, cytoplasmic vesicles, prominent Golgi complex, and rough endoplasmic reticulum. Compared with controls, rIL-4 treated cells displayed increased expression of MHC class II molecules and of Migration Inhibitory Factor-Related Protein-14. Whereas mannose receptor-mediated phagocytosis was increased, Fcgamma-receptor mediated phagocytosis and the production of nitric oxide were decreased in treated cultures. All these features overlap those reported for ECs from granulomatous lesions. In conclusion, treatment of mouse peritoneal macrophages with rIL-4 drives their in vitro differentiation to an epithelioid phenotype and provides a tool to investigate the biology of ECs.

Cytologic findings of epithelioid angiosarcoma of the thyroid. A case report.

BACKGROUND: Angiosarcoma of the thyroid is a rare and aggressive tumor and occurs mainly in patients from central Europe, especially the alpine region. The fine needle aspiration findings of a keratin-positive epithelioid angiosarcoma of the thyroid occurring in a nonmountainous area in South America is described. CASE: A 65-year-old male from São Paulo, Brazil, presented with a mass in the anterior part of the neck with progressive enlargement for three months. The cytologic findings on the fine needle aspirate were a cellular smear composed of single cells and small clusters of neoplastic cells, oval and round. Cell borders were indistinct, and the cytoplasm was vacuolated. The nuclei were eccentrically located, with irregular nuclear membranes; single, prominent nucleoli; and a coarse chromatin pattern. Features suggestive of intracytoplasmic lumens were identified. Open surgical biopsy demonstrated a tumor infiltrating the thyroid gland and composed of large, round, atypical epithelioid cells lining vascular spaces. These neoplastic cells were immunoreactive for AE1:AE3, CK7, vimentin, CD31 and factor VIII. CONCLUSION: Epithelioid angiosarcoma should be considered in the differential diagnosis of epithelioid neoplasms of the thyroid. An immunohistochemical panel should include vascular markers even in the presence of immunoreactivity for epithelial markers.

Angiomatose epitelióide bacilar / Bacillary epithelioid angiomatosis

A angiomatose epitelóide bacilar foi descrita, primeiramente, em 1983 por Stoler e cols, em paciente aidético. O agente etiológico assemelha-se a um organismo Rickéttsia-símile relacionado a Rochalimaea quintana, facilmente observado em cortes histológicos pela técnica de Warthin-Starry. O tratamento é feito com a eritromicina. As lesöes cutâneas säo variadas, constituindo pápulas, placas ou nódulos. Lesöes sistêmicas säo descritas em pacientes com a síndrome de imunodeficiencia adquirida. O diagnóstico diferencial deve ser feito com o sarcoma de Kaposi e o granuloma piogênico. O quadro histopatológico é marcado por intensa proliferaçäo de vasos com singular revestimento epitelóide e grande número de bacilos