Immunoglobulin-Storing Histiocytosis: A Case Based Systemic Review

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Crystal-storing histiocytosis (CSH) is a rare manifestation of monoclonal gammopathies, characterized by immunoglobulin accumulation in histiocytes.
• Immunoglobulin-storing histiocytosis (IgSH) represents a non-crystallized form, presenting unique diagnostic challenges.

Purpose of the Study:

• To report a case of non-crystallized IgSH in a patient with IgG kappa monoclonal gammopathy of undetermined significance (MGUS).
• To conduct a comprehensive literature review of IgSH cases to delineate its characteristics and clinical associations.

Main Methods:

• Case presentation of a 75-year-old female with IgSH.
• Systematic literature search for IgSH cases diagnosed between 1987 and 2020.
• Analysis of patient demographics, associated disorders, affected organs, and immunoglobulin characteristics.

Main Results:

• A total of 140 IgSH cases were identified in the literature review.
• The median age at diagnosis was 60 years, with a near-equal sex distribution.
• Commonly associated conditions included multiple myeloma, MGUS, and lymphoplasmacytic lymphoma.
• Predominant organ involvement included bone, head and neck, kidney, lung, and the gastrointestinal tract.
• IgG was the most frequent immunoglobulin class, with a strong association with kappa light chain expression.

Conclusions:

• IgSH is a rare but significant entity associated with monoclonal gammopathies.
• IgSH should be considered in cases with unusual organ system involvement and monoclonal gammopathy, especially those with kappa light chain expression.