| Session: Mast cell disease |
| Case number: 083 |
Submitter(s): Ana Maria Medina, Antonio E. Martinez, Amilcar Castellano-Sanchez.
Clinical history
The patient is a 66 year-old man who presented to the emergency room of our institution with a chief complain of left flank pain. He also complained of having cough for the past five months. His medical history was pertinent for hypothyroidism, and Syntroid was the only medication he was taking at home. He denied any other symptoms, and skin lesions were absent. A CT of the abdomen was performed, showing splenomegaly. A CBC revealed anemia and thrombocytopenia with an increased WBC count with mild eosinophilia. The patient was admitted to the hospital and scheduled for a splenectomy.
CBC
WBC (10^3/uL): 19.67
RBC (10^6/uL): 3.01
HGB (g/dL): 8.9
HCT (%): 27.5
MCV (fL): 91.4
RDW (%): 20.7
PLT (10^3/uL): 42
MPV (fL): 10.9
NEUT (%): 57
LYMPH (%): 20
MONO (%): 13
EOS (%): 10.
Details of gross/microscopic pathology:
The spleen was received unfixed weighing 1736 grams and measuring
26 x 17.5 x 10 cm. The external surface was pink-purple and mottled. Cut section revealed mottled, pink-red, granular parenchyma with two, subcapsular, round white-brown areas measuring up to 1.5 cm in greatest dimension consistent with splenic infarcts. The H&E sections demonstrated overall preservation of the splenic architecture. There were collections of oval to spindled cells located primarily within the red pulp, and in the vicinity of the white pulp follicles (Figs. 1, 2). The cells had pale cytoplasm (rare cells contained barely discernable amphophilic granules) and oval to elongated nuclei (Fig. 3). Deposits of hemosiderin pigment were noted. Among the cellular infiltrates were scattered eosinophils. The surrounding cords of Billroth and sinuses were morphologically unremarkable. A significant myeloid cell population was not seen.
Immunophenotype (flow cytometry/immunohistochemistry):
CD117 (Fig. 4), CD25 (Fig. 5) and CD68 (Fig. 6) immunohistochemical stains decorated the mast cells in the aforementioned aggregates. A Leder histochemical stain (Fig. 7) highlighted sparse cytoplasmic granules in a subpopulation of the same. CD20 and CD3 immunohistochemical stains showed B-and-T-cells in the usual distribution, respectively.
Flow cytometry
Flow cytometric analysis failed to reveal a monoclonal B-cell or an aberrant T-cell population.
Cytogenetics:
Molecular analysis:
Interesting feature(s) of submitted case:
A 66 year-old man presented to the emergency room with left flank pain. A CT of the abdomen showed splenomegaly. The patient was admitted to the hospital and was scheduled for a splenectomy. The spleen weighed 1736 grams. The cut surface revealed a mottled, pink-red, granular soft parenchyma. Histologic examination revealed collections of oval to spindled cells with eosinophilic cytoplasm associated with eosinophils. Leder, CD117, CD25 and CD68 supported the diagnosis of mast cell disease. Mast cell disease should therefore be considered as a differential diagnosis in patients with splenomegaly of unknown etiology.
Proposed diagnosis:
Spleen with mast cell disease.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Studies performed by the panel: positive for D816V mutation, CD25+
Images:
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