[1228] “In Situ” Mantle Cell Lymphoma (MCL), an Incidental Finding with an Indolent Clinical Course.

Alejandra Carvajal, Luz Sua, Nhora Silva, Stefania Pittaluga, Cristina Royo, Rachel L Sargent, Fina Climent, Samuel A Jacobs, Jan Delabie, Kikkeri Naresh, Adam Bagg, Nancy L Harris, Steven H Swerdlow, Elaine S Jaffe, Elias Campo. Hospital Clínic, Barcelona, Spain; MD Anderson Cancer Ctr, Houston, TX; University of Pittsburgh, PA; Oslo University Hospital, Norway; Hammersmith Hospital, London, United Kingdom; Hospital of the University of Pennsylvania, Philadelphia; Massachusetts General Hospital, Boston; National Cancer Institute, Bethesda, MD

Background: The term “in situ” MCL has been used to define cases with a restricted distribution of the cyclin D1+ cells in the mantle zone of the follicles in the context of a reactive lymphoid tissue. The expression of SOX11, a transcription factor strongly expressed in virtually all conventional MCL, is negative in a subgroup of MCL with an indolent clinical course. The clinical and biological significance of "in situ" MCL and the expression of SOX11 in these lesions is unknown.
Design: We have investigated 17 "in situ" MCL with a panel of markers including SOX11. The t(11;14) was studied in 8 cases by conventional cytogenetics or FISH and in one of them combining FISH and cyclin D1 staining (FICTION).
Results: There were 9 males and 8 females (median age 65 yrs). 9 cases presented in a solitary lymph node, 2 in more than one lymph node and 6 were extranodal. Peripheral blood was involved in 3 of 8 cases. One patient had cyclin D1+ cells in a gastric biopsy. The t(11;14) was detected in all cases and it was seen in cyclin D1+ cells by FICTION. 4 cases had other simultaneous lymphoid neoplasms (2 CLL, 1 “in situ” follicular lymphoma and 1 marginal zone lymphoma). SOX11 was expressed in 7 of 16 cases (44%). Leukemic cells were detected in 3 of the 5 SOX11- but in none of the 3 SOX11+ cases examined. Nine patients were followed more than 1 year. 7 had been managed with watchful waiting and 2 with chemotherapy. Only one untreated patient with a SOX+ tumor developed an overt MCL 4 years after the diagnosis. Four untreated patients with a SOX11- tumor were alive with stable lymphocytosis (3) or no detectable disease (1) after 5 to 19 yr (median 8 yr). Two untreated patients (one SOX11+ and one negative) died of an unrelated disease 1-1.4 yr after diagnosis. The two patients treated with chemotherapy (both SOX11+) were alive with no evidence of disease 4 and 4.5 years after diagnosis.
Conclusions: “In situ” MCL is an incidental finding not infrequently associated with other lymphoid neoplasms and more frequently SOX11 negative than conventional MCL. Most patients have an indolent course, even without treatment.These cases must be distinguished from overt MCL because they may not require aggressive treatment strategies.
Category: Hematopathology

Monday, February 28, 2011 8:00 AM

Platform Session: Section B, Monday Morning


Close Window