Some myxoinflammatory fibroblastic sarcomas are dominated by very large epithelioid cells
with abundant eosinophilic cytoplasm and eccentric nuclei (hematoxylin-eosin, original magnification X400).
In 2002, the WHO defined PEComa as a mesenchimal tumor that contains perivascular epithelioid cells
presenting histological and immunohistochemical differences (7).
The epithelioid cell
in tuberculosis is secretory and not a macrophage.
Our observation of an increase in granulomas in two patients with coexisting T1R at the completion of treatment could be explained as due to the effective bacterial killing resulting in improved immunity, enabling the host to mount a granulomatous response with abundance of protective epithelioid cells
4) The smooth muscle component is derived from the perivascular epithelioid cell
(PEC), and hence, AML is one of a number of tumors classified under the general term PEComa, a group that includes clear cell tumor and lymphangioleiomyomatosis.
13 In our study, among type 1 reaction patients lymphocytic infiltrate (96%), dermal edema (93%), epithelioid cells
(78%) and giant cells (Langhans type) (15%) were the common histological findings.
Thus, toward TT end of the spectrum, histopathology shows epithelioid cells
, Langhans giant cells, and lymphocytes, and toward LL end of spectrum, more foamy macrophages are observed.
Microscopic findings: The consistent histologic findings in all cases were diffuse granulomas characterized by extensive foamy poorly basophilic macrophages, epithelioid cells
and lymphocytes infiltration into the mucosa and submucosa of the small intestine with numerous acid-fast organisms (figure 2a).
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).
Specific lesions are characterized by the presence of granulomas of epithelioid cells
without necrosis on biopsy specimens.
Disseminated histiocytic infiltration of either aggregates or sheets of epithelioid cells
containing acid-fast bacilli, in the absence of caseous necrosis, were observed in different organs of the infected doves, especially lungs (23/23), intestines (9/23).
Histologically, the pattern of tuberculous lymphadenitis may vary from a collection of few epithelioid cells
in a background of mild reactive changes and noncaseating granulomas to caseating granulomas and complete necrosis.
showed dense cytoplasm and distinct cell borders (Figure 2).
A--Heart granuloma showing epithelioid cells
and lymphocytes between cardiomyocytes (autopsy exam, HEx100); B--Liver granuloma showing giant and epithelioid cells
and lymphocytes in the periphery; some of the hepatocytes display macrovesicular steatosis (autopsy exam, HEx100); C--Caseating granuloma of the pancreas showing caseous necrosis, epithelioid cells
and lymphocytes in the periphery next to normal acini (autopsy exam, HEx100); D--Caseating granuloma of the kidney medulla showing caseous necrosis, giant cells and lymphocytes (autopsy exam, HEx100); E--Caseating granuloma of the spleen (autopsy exam, HEx100).
Angiomyolipoma (AML) are benign tumours composed of varying amounts of thick-walled dysplastic blood vessels, smooth muscle and mature adipose tissue derived from epithelioid cells