Crystal-storing histiocytosis associated with MALT Lymphoma: a case report and literature review.

INTRODUCTION AND IMPORTANCE

Crystal-storing histiocytosis (CSH) is a rare, non-neoplastic histiocytic proliferation that often complicates underlying lymphoproliferative or plasma cell disorders. The respiratory system is uncommonly involved in CSH. We present a local case of pulmonary CSH associated with marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT), along with eight additional cases identified from a literature review.

CASE PRESENTATION

A 64-year-old woman was admitted to the hospital for coughing, expectoration, and asthma for more than 1 year. Chest CT revealed localized thickening of the tracheal wall, and the bronchoscopy examination showed neoplasms of the trachea and bronchus mucosa. The lesion was characterized by sheets of histiocytes with abundant eosinophilic cytoplasm and scattered aggregates of atypical lymphoid cells. Immunohistochemical stains and T/B-cell gene rearrangement studies supported the pathological diagnosis of CSH-associated MALT. The patient remained free from the disease after lesion resection via bronchoscopy, with further treatment of targeted therapy.

CLINICAL DISCUSSION

Pulmonary CSH-associated MALT can occur in patients of various ages and genders with non-specific clinical and imaging features. Histopathological examination is essential for differentiating CSH from similar conditions. The pathogenesis of CSH may relate to the overproduction of immunoglobulins, and the immunoglobulin types involved in the cases we described are predominantly kappa light chains.

CONCLUSION

Recognizing CSH is essential for starting a clinical evaluation to identify the underlying neoplasm or associated causes. A conclusive diagnosis relies on pathological examination. More detailed case reports are needed to clarify pathogenesis and improve diagnosis, treatment strategies, and patient outcomes.