Histiocytoid breast carcinoma: Solid variant of invasive lobular carcinoma with decreased expression of both E-cadherin and CD44 epithelial variant.

Fujiwara, Masachika; Horiguchi, Miwa; Mori, Satoshi; Yokoyama, Koichi; Horiguchi, Hisashi; Fukazawa, Masakatsu; Fujiwara, Hiromi; Yano, Yukiko; Satoh, Hiroaki; Kamma, Hiroshi

Histiocytoid breast carcinoma (HBC) is a rare type of breast carcinoma with morphologic characteristics resembling those of histiocytes. Described herein are cytological and histological findings in a case of HBC. Fine-needle aspiration cytology revealed numerous loosely cohesive tumor cells with abundant foamy to granular cytoplasm and bland-appearing nuclei. The resected tumor exhibited a solid growth pattern instead of classic invasive lobular patterns observed in most reported cases of HBC. However, distinct intracytoplasmic lumina and Pagetoid extension to ducts suggested that this tumor was a variant of invasive lobular carcinoma. To determine the cause of the loose cellular cohesiveness of this HBC, its expression of the epithelium-related cell adhesion molecules E-cadherin and CD44v8-10 (CD44 epithelial variant) was examined. Immunohistochemically, E-cadherin was not detected, similar to most lobular carcinomas. Furthermore, competitive reverse transcription–polymerase chain reaction (RT-PCR) analyses among alternatively spliced variants of CD44 revealed that the ratio of expression of CD44v8-10 to that of CD44v10 (dominant variant in leukocytes) was lower than that for the reference breast carcinoma samples. It is concluded that the present case of HBC was a solid variant of invasive lobular carcinoma exhibiting foamy to granular cytoplasmic change. Decreased expression of both E-cadherin and CD44 epithelial variant may be responsible for the loose cellular cohesiveness observed in HBC.

BREAST cancer; MACROPHAGES; CYTOLOGY; CADHERINS; GENE expression; IMMUNOHISTOCHEMISTRY

Pathology International, 2005, Vol 55, Issue 6, p353

1320-5463

Academic Journal

10.1111/j.1440-1827.2005.01836.x