Gastric malt lymphoma with crystalline immunoglobulin inclusions and secondary immunoblastic lymphoma in a cervical lymph node

Crystalline plasma cell inclusions in helicobacter-associated gastritis

BACKGROUND

Crystalline cytoplasmic inclusions are well documented in B cell lymphomas but have rarely been described in reactive plasmacytic infiltrates.

AIM

Three cases of Lelicobacter-associated gastritis are described in which plasma cells focally contained rhomboid and needle-shaped crystalline inclusions.

METHODS

Crystalline inclusions were identified in the gastric biopsy specimens from three patients undergoing routine upper gastrointestinal endoscopy. The cells were characterised immunohistochemically using the following antisera: cytokeratin, leucocyte common antigen, desmin, CD20, CD68, CD79a, CD138, immunoglobulin (Ig)G, IgA and IgM heavy chains, and kappa and lambda Ig light chains. Clinical follow-up data were obtained.

RESULTS

All biopsies showed a Lelicobacter-associated active chronic gastritis. Variable numbers of plasma cells with intracytoplasmic crystalline inclusions in the superficial lamina propria were seen. The crystals were not stained with any of the antisera tested, but the cells containing the crystals expressed CD79a and CD138 and, in the two assessable cases, showed IgA and lambda light chain immunoreactivity. The more numerous morphologically normal plasma cells in each patient were polytypic, and there were no histological features to suggest lymphoma. Crystals were not identified in the plasma cells in mucosal biopsy specimens from other sites in any of the patients.

CONCLUSIONS

Crystalline inclusions in plasma cells can occur in association with Lelicobacter gastritis. Although light chain restriction was shown in two patients, the overall histological and clinical findings indicated a reactive process. The presence of plasma cell crystals in isolation should not be considered to be diagnostic of lymphoma.

Intracytoplasmic immunoglobulin crystals in follicular lymphoma

We report a case of follicular lymphoma with crystal inclusions. Swollen lymph nodes taken from the left neck of a 53- year-old Japanese woman were replaced by follicular proliferation of atypical centroblastic and centrocytic cells with intracytoplasmic crystal inclusions. The crystals were confined to lymphoma cells and were not found in histiocytes. Lymphoma cells were positively immunostained with lambda light chain and mu heavy chain, but the crystals were only weakly so. In situ hybridization of light chains disclosed a monoclonal expression of lambda light chain mRNA in lymphoma cells. The crystals had a periodic linear substructure with about 5-nm intervals. The worldwide literature reports 8 cases, including the current case of non-Hodgkin's lymphoma with crystals confined to the neoplastic cells. The cases did not accompany paraproteinemia and crystal-storing histiocytosis and appear to follow a favorable clinical outcome.

Transformation of monocytoid B-cell lymphoma to large cell lymphoma associated with crystal-storing histiocytes

We report a case of crystal-storing histiocytosis associated with large cell lymphoma in a patient with a history of monocytoid B-cell lymphoma 10 years previously. The cervical lymph node biopsy showed a diffuse proliferation of large lymphocytes with vesicular nuclear chromatin and distinct nucleoli. These lymphocytes were associated with numerous immunoglobulin lambda light-chain crystal-storing histiocytes, which morphologically resembled rhabdomyoblasts. Occasional lymphoid cells also showed large immunoglobulin crystals. This case establishes the association of crystal-storing histiocytes with lymphomas of mucosa-associated lymphoid tissue and emphasizes the need for immunophenotyping to distinguish these unusual cases from other tumors, particularly adult rhabdomyomas.

Intracellular crystalline deposits in lymphoplasmacellular disorders

Crystalline immunoglobulin intracellular inclusions may be found in a range of B-cell neoplasias, including MALT (mucosa-associated lymphoid tissue) lymphoma. The crystals are regarded as an outcome of impaired cell secretory activity leading to their accumulation. At times the deposits may be so profound as to obscure the diagnosis and may even lead to misdiagnosis. Examples of the crystals are presented along with a brief literature review.