Case Presentation

A 62-year-old patient presented with progressive abdominal fullness, early satiety, and left upper quadrant discomfort. On examination, there was marked splenomegaly.

Initial laboratory evaluation showed leukocytosis (WBC 19 x10⁹/L) lymphocytes: 14.6 x 10⁹/L Neutrophil: 4.12x10⁹/L Monocyte: 0.54 x10⁹/L Eosinophil: 0.09x10⁹/L Basophil: 0.16 x 10⁹/L Hemoglobin: 13.5 g/dl  Platelet count: 391x10⁹/L.

 Peripheral blood smear demonstrated medium-sized lymphocytes with irregular, hairy-like cytoplasmic projections, raising suspicion for hairy cell leukemia and hairy cell leukemia variant.

Flow cytometry showed a clonal B-cell population positive for CD19, CD20, CD22, CD20,CD22,CD79b,CD43,FMC7,CD11c with lambda light chain restriction, and negative for CD25,CD103,and CD123,CD25,CD5,CD10 and CD200,findings consistent with splenic marginal zone lymphoma.

A CT scan of the abdomen and chest revealed massive splenomegaly and enlarged lymph nodes above and below the diaphragm, indicating systemic disease involvement.

A diagnosis of splenic marginal zone lymphoma (SMZL) presenting with hairy-like lymphocytes, splenomegaly, and lymphadenopathy was established.

Learning Points

1.  Lymphocytes with hairy projections are characteristic but not exclusive to hairy cell leukemia.
2. SMZL commonly presents with massive splenomegaly:
   Many patients have few systemic symptoms, and splenic enlargement may be the dominant clinical finding.
3. Lymphadenopathy can occur:
   Although SMZL traditionally presents with isolated splenomegaly, enlarged lymph nodes above and below the diaphragm indicate more disseminated disease.
4. Flow cytometry is essential for distinguishing SMZL from hairy cell leukemia (HCL)
   Key differentiators:

SMZL: negative for CD25, CD103, CD123,and these markers are positive in HCL.