Open AccessSmall cell variant of mantle cell lymphoma is an indolent lymphoma characterized by bone marrow involvement, splenomegaly, and a low Ki‐67 index
Author(s) -
Kimura Yoshizo,
Sato Kensaku,
Imamura Yutaka,
Arakawa Fumiko,
Kiyasu Junichi,
Takeuchi Masanori,
Miyoshi Hiroaki,
Yoshida Maki,
Niino Daisuke,
Sugita Yasuo,
Morito Toshiaki,
Yoshino Tadashi,
Nakamura Shigeo,
Ohshima Koichi
Publication year - 2011
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2011.01988.x
Subject(s) - mantle cell lymphoma , cyclin d1 , lymphoma , medicine , immunohistochemistry , mantle zone , bone marrow , chronic lymphocytic leukemia , pathology , neoplasm , cancer research , b cell , cancer , leukemia , immunology , cell cycle , antibody , germinal center
Mantle cell lymphoma (MCL) is recognized as a well‐defined B cell neoplasm characterized by overexpression of cyclin D1 (CCND1), with “classical” and “aggressive” variant subtypes. A small‐cell variant of MCL (small‐MCL), resembling small lymphocytic lymphoma/chronic lymphocytic lymphoma (CLL/SLL), has been added to the World Health Organization classification. However, to the best of our knowledge, there have been no studies focusing on this neoplasm. In the present study, we analyzed 15 cases of CCND1‐positive small‐MCL, including immunohistochemical analysis of Ki‐67 and CCND1 expression, and compared our findings with those of 151 cases of classical MCL. Morphologically, most small‐MCL showed a diffuse growth pattern (76.9%), whereas others featured a very thin mantle zone pattern resembling a reactive follicle (23.1%). Bone marrow involvement and splenomegaly occurred significantly more frequently in small‐MCL than in classical MCL ( P < 0.05). Ki‐67 expression in small‐MCL was lower than in classical MCL (mean [±2 SD] 12.5 ± 17.3% and 25.2 ± 25.5%, respectively; P < 0.001), but there was no significant difference in CCND1 expression ( P = 0.2445). The 5‐year survival rate in small‐MCL was 83.3%. Although there was no significant difference in outcome between small‐MCL and classical MCL ( P = 0.287), only one small‐MCL patient died of the disease. Thus, small‐MCL constitutes a specific subset of indolent lymphoma with distinguishing features, possibly making a major contribution to the accuracy of therapeutic decisions. In addition, clinicians should be aware of the possible presence of small‐MCL to avoid making a misdiagnosis of follicular hyperplasia or CLL/SLL. ( Cancer Sci 2011; 102: 1734–1741)