Details
This 45 year old man presented to the Emergency Department with a three week history of fevers, night sweats, weight loss, abdominal rash, diarrhea and intermittent rashes. Diagnostic imaging revealed generalized lymphadenopathy, hepatosplenomegaly and ascites. Blood work demonstrated thrombocytopenia of 45. Bone marrow biopsy was arranged, however patient returned with high fevers and a CT scan with possible duodenal perforation. Surgical resection of a perforated ulcer with anastomosis was completed. Surgical pathology demonstrated small bowel with an abnormal infiltration of mast cells with mucosal ulceration and granulation issue.
By immunohistochemistry, the lesional cells show diffuse strong CD68 and CD117 staining. CD2 and CD3 highlight T-cells, CD20 highlights B-cells, CD34 highlights vessels and pankeratin stains mucosa. Ki-67 proliferation index is low and is estimated to be <5%. Postoperatively, the patient was admitted to ICU and slowly deteriorated. Palliative care team was involved and the patient passed away.
Systemic mastocytosis is a clonal, neoplastic proliferation of mast cells caused by a CKIT mutation. It can involve one or multiple organ systems. It commonly involves bone marrow, skin and GI tract and can occur at any age. Clinical symptoms are grouped into 4 categories: constitutional symptoms, skin manifestations, mediator-related systemic events and musculoskeletal complaints.
Systemic mastocytosis is diagnosed with one major and one minor criterion or at least three minor criteria.
Major criterion is multifocal, dense infiltrates of mast cells (>15 mast cells).
Minor criteria:
1. Biopsy with >25% mast cells are spindle-shaped or atypical
2. Activating point mutation of CKIT at codon 816
3. Mast cells positive for CD2 and/or CD25 in addition to normal mast cell markers
4. Total serum tryptase >20 ng/mL.
Currently there is no cure and prognosis depends on disease category. Generally, cutaneous forms have a better outcome than systemic forms, and mast cell leukemia (>20% mast cells on bone marrow aspirate, or >10% of peripheral white blood cells on blood smear) has the worst prognosis.
This slide shows H&E stain. See related content for CD68 and CD117 stains.
See LMP10785 & LMP68621 – Bone Marrow, Systemic mastocytosis for bone marrow biopsy sections from different cases (links in related content).
