[1449] Clinicopathologic and Molecular Features of Crystal (Immunoglobulin) Storing Histiocytosis Associated with Lymphoplasmacytic Neoplasms

Rashmi Kanagal-Shamanna, Donna M Weber, Robert Z Orlowski, Pei Lin, Roberto N Miranda, Carlos E Bueso-Ramos, L Jeffrey Medeiros, Ken H Young. The University of Texas MD Anderson Cancer Center, Houston

Background: Crystal-storing histiocytosis (CSH) is a rare lesion that results from the intra-lysosomal accumulation of immunoglobulins (Igs). CSH has been reported in patients with plasma cell myeloma (PCM), plasmacytoma, lymphoplasmacytic lymphoma (LPL), light-chain disease, and amyloidosis. The biological mechanism(s) for the development of CSH is not clear, but may be the result of high serum Ig level and the abnormal intrinsic physicochemical or structural properties of the Ig secreted by the neoplastic cells. A single case has been reported with unusual amino acid substitutions in the variable region of the stored kappa light chain (LC) (Lebeau et al. Blood. 2002; 100: 1817-1827). There are no published data on alterations of lambda LC, DNA, RNA or protein.
Design: We retrieved all CSH cases from the pathology files of our institution. Histologic changes and immunohistochemical studies were reviewed and correlated with clinical outcome. Mass spectrometric analysis was undertaken in 5 cases to define structural abnormalities of the Ig.
Results: 11 cases of CSH were identified, including 6 men and 5 women with a median age of 51 years (range, 33-79). CSH involved gastrointestinal tract/GIT (n=4), bone marrow/BM (n=3), lymph node (n=1), spleen (n=1), skin (n=1), lung (n=1) and soft tissue mass of cheek (n=1). CSH was associated with a low grade plasmacytoid B-cell neoplasm, either marginal zone lymphoma (MZL) or lymphoplasmacytic lymphoma (LPL), in 7 patients. Two patients with CSH had PCM. In 1 patient, CSH was detected in a lung biopsy whereas BM showed relapsed B-lymphoblastic lymphoma. In 1 patient without evidence of prior malignancy, CSH involved the GIT. In 10/11 cases, there was significant histiocytic component comprising at least 50% of the biopsy cellularity. Immunoglobulin LCs were detected within histiocytes: kappa in 7/11 cases and lambda in 4/11 cases. Survival data was available in 8 patients, of which 4 patients are alive. The median survival time was 32 months, (range, 1.2–44), which is significantly shorter compared with patients with either LPL or MZL.
Conclusions: CSH usually presents with a prominent histiocytic component that obscures the underlying lymphoma, and thereby can be a diagnostic challenge. CSH is commonly associated with a lymphoplasmacytoid neoplasm, and predicts a poor prognosis. Rarely, CSH can be a sole pathologic finding. Unlike earlier studies, CSH can be associated with either kappa or lambda LCs. Spectrometric analysis may provide biological insights into pathogenesis.
Category: Hematopathology

Monday, March 19, 2012 1:00 PM

Poster Session II # 220, Monday Afternoon


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