Histiocytoid breast carcinoma: solid variant of invasive lobular carcinoma with decreased expression of both E-cadherin and CD44 epithelial variant.
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.
Fujiwara
Masachika
M
Department of Pathology, Kensei General Hospital, Iwase, Nishi-Ibaraki, Japan.
Horiguchi
Miwa
M
Mori
Satoshi
S
Yokoyama
Koichi
K
Horiguchi
Hisashi
H
Fukazawa
Masakatsu
M
Fujiwara
Hiromi
H
Yano
Yukiko
Y
Satoh
Hiroaki
H
Kamma
Hiroshi
H
D000368:Aged; D017398:Alternative Splicing; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D015820:Cadherins / Q000096:biosynthesis*; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006644:Histiocytes / Q000473:pathology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000096:biosynthesis* / Q000235:genetics; D007150:Immunohistochemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
C117722:CD44v10 antigen; D015820:Cadherins; D018960:Hyaluronan Receptors