title: Small cell variant of mantle cell lymphoma is an indolent lymphoma characterized by bone marrow involvement, splenomegaly, and a low Ki-67 index.
abstract: 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.
authors: Department of Pathology, School of Medicine, Kurume University, Kurume, Japan. yoshizo830@yahoo.co.jp
authors: Yoshizo
authors: Y
authors: Kimura
authors: Kensaku
authors: K
authors: Sato
authors: Yutaka
authors: Y
authors: Imamura
authors: Fumiko
authors: F
authors: Arakawa
authors: Junichi
authors: J
authors: Kiyasu
authors: Masanori
authors: M
authors: Takeuchi
authors: Hiroaki
authors: H
authors: Miyoshi
authors: Maki
authors: M
authors: Yoshida
authors: Daisuke
authors: D
authors: Niino
authors: Yasuo
authors: Y
authors: Sugita
authors: Toshiaki
authors: T
authors: Morito
authors: Tadashi
authors: T
authors: Yoshino
authors: Shigeo
authors: S
authors: Nakamura
authors: Koichi
authors: K
authors: Ohshima
references: Ann Oncol. 2010 Jan;21(1):133-9
references: 20019090
references: Blood. 2008 Oct 1;112(7):2687-93
references: 18625886
references: Ann Oncol. 1995 Mar;6(3):257-62
references: 7612491
references: Histopathology. 2003 Aug;43(2):135-43
references: 12877728
references: J Clin Oncol. 2009 Mar 10;27(8):1209-13
references: 19188674
references: Hum Pathol. 2003 Oct;34(10):1030-4
references: 14608537
references: Br J Haematol. 2008 Oct;143(2):248-52
references: 18729857
references: J Clin Oncol. 2005 Mar 20;23(9):1984-92
references: 15668467
references: J Egypt Natl Canc Inst. 2005 Dec;17(4):279-90
references: 17102815
references: Int J Cancer. 2002 Mar 20;98(3):470-4
references: 11920602
references: N Engl J Med. 1993 Sep 30;329(14):987-94
references: 8141877
references: Hum Pathol. 2005 Nov;36(11):1232-7
references: 16260278
references: Blood. 2003 May 15;101(10):4042-6
references: 12511405
references: Blood. 2003 Jun 15;101(12):4975-81
references: 12609845
references: Blood. 1999 Sep 15;94(6):1840-7
references: 10477712
references: J Clin Oncol. 2005 Oct 1;23(28):7013-23
references: 16145068
references: J Clin Oncol. 2009 Feb 1;27(4):511-8
references: 19075279
references: J Clin Pathol. 1987 Jun;40(6):642-51
references: 3497180
references: Am J Hematol. 2000 Jul;64(3):190-6
references: 10861815
references: Leukemia. 2001 Nov;15(11):1785-91
references: 11681422
references: Pathol Int. 2001 Oct;51(10):747-61
references: 11881727
references: Eur J Haematol. 2002 Jul;69(1):11-20
references: 12270057
references: Cancer Cell. 2003 Feb;3(2):185-97
references: 12620412
references: Blood. 1994 Jul 15;84(2):403-7
references: 8025269
references: Cancer Res. 2010 Feb 15;70(4):1408-18
references: 20124476
references: Br J Haematol. 2005 Oct;131(1):29-38
references: 16173960
references: Cancer Sci. 2010 Mar;101(3):806-14
references: 20002441
references: Eur J Haematol. 2002 Jan;68(1):12-21
references: 11952817
references: Leuk Lymphoma. 2000 Aug;38(5-6):541-5
references: 10953975
references: Blood. 2003 May 15;101(10):4047-54
references: 12637326
references: Virchows Arch. 2008 Oct;453(4):407-11
references: 18696109
references: Blood. 1997 Mar 15;89(6):2067-78
references: 9058729
references: Blood. 1999 Sep 15;94(6):1848-54
references: 10477713
references: Haematologica. 2009 Nov;94(11):1555-62
references: 19880778