Photomicrographs of HE stained sections show a renal cell carcinoma (RCC) with tumor cells arranged in nests separated by thin vascular septae (a; x200); high magnification shows marked nuclear pleomorphism (b; x400); areas of angiomyolipoma (AML) composed of spindled and small epithelioid cells
(c; x200) with uniform round to oval nuclei are present (d; x400); at places the spindled cells originate from walls of abnormal blood vessels (e; x200).
Careful cytomorphologic evaluation during the FNA on-site assessment revealed the presence of cohesive sheets of epithelioid cells
exhibiting disordered honeycombing, 3-dimensional clusters with community borders, and acinar arrangements.
Histologically, it is characterized by solid sheets or nests of epithelioid cells
with cellular pleomorphism, increased mitotic activity, eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli.
6-cm focus showing moderately sized epithelioid cells
within a fibromyxoid background was also present.
A, Case 490 (SW0 negative): primary lesion showing atypical intraepidermal lentiginous proliferation of large melanoma cells with suprabasal pagetoid spread (arrows) and extensive dermal infiltration I epithelioid cells
with nuclear atypia and focal pigmentation (arrowheads).
Histologic examination of lung, lymph nodes, spleen, liver, and brain showed granulomatous inflammation with predominantly macrophages, epithelioid cells
(in the lung, including bronchioles), and some multinucleated giant cells.
On histologic examination, areas of necrosis in the lungs were extensively infiltrated with acid-fast positive bacilli surrounded by macrophages, epithelioid cells
, and giant cells.
Histologic examination demonstrated epithelioid cells
arranged in papillae, cords and solid nests.
Other lymphokines cause the activation and differentiation of recruited monocytes into activated macrophages, giant cells, and epithelioid cells
, the characteristic cells of sarcoid granulomata (2).
with well-formed vascular lumens, consistent with an epithelioid hemangioma.
In the study by Argani et al, (7) the TFE3-positive PEComas were found in younger patients without evidence of tuberous sclerosis, and the lesions were composed of predominantly epithelioid cells
in an alveolar pattern with minimal immunoreactivity for muscle markers.
The epithelioid cells
are slightly elongated, with associated large mucus-containing physaliphorous cells (figure 2).