A 66‐year‐old man without any medical history presented with fatigue, weight loss, and generalized abdominal pain for 3 months. Physical exam revealed splenomegaly. Labs disclosed hemoglobin of 8.0 g/dL and platelets of 79,000/μL. CAT scan of the abdomen showed splenomegaly and diffuse lymph node (LN) enlargement. An endoscopic biopsy of the porta hepatis LN was performed. A few hours after endoscopy, the patient complained of sudden rigor, became unresponsive, and a medical code was called. Monitor showed ventricular fibrillation. The patient was successfully resuscitated after 4 defibrillations. As the LN biopsy was inconclusive, a bone marrow (BM) biopsy was performed. This revealed mastocyte infiltration, peritrabecular spindle cell infiltrates positive for CD117, weakly positive for CD45 and CD43, consistent with systemic mastocytosis. Serum tryptase, a marker for mastocytosis activity, was elevated to 835 ng/mL (normal, 5–10 ng/mL). This decreased to 457 ng/mL with imatinib mesylate therapy. However, the patient developed abdominal distension, and his hemoglobin acutely declined. A repeat CAT scan showed new splenic hemorrhage with massive ascites. Splenic embolization was performed. As paracentesis revealed spontaneous bacterial peritonitis, broad‐spectrum antibiotics were administered. Despite treatment, the patient continued to deteriorate and died approximately 2 months after the diagnosis of systemic mastocytosis (SM).
Mastocytosis is a rare hematologic disorder with unknown incidence. SM is when mastocytes accumulate in multiple organs such as the skin, spleen, BM, and LNs. As in our case, patients with SM present with generalized symptoms from organ impairment due to mastocyte infiltration. Clinical presentation may mimic those of lymphoma/leukemia. The World Health Organization SM criteria require 1 major criterion and 1 minor criterion or at least 3 minor criteria for diagnosis. The major criterion is multifocal infiltrates of mastocytes in the BM and/or other organs. Minor criteria include more than 25% of mastocytes having spindle‐shaped or atypical morphology, point mutation at codon 816 (KIT), mastocytes expressing CD2 and/or CD25 with normal mastocyte markers, and serum tryptase exceeding 20 ng/mL. A danger in SM is that during diagnostic biopsies, mediator‐related events can occur. The mediator release may be triggered by any physical/emotional stress or by drugs; general anesthesia is of particularly high risk. Close communication among the primary medical team, anesthesiologists and surgeons is essential. Obtaining preprocedure tryptase and considering telemetry monitoring of tryptase positive patients with bedside preparation of epinephrine, H1/H2 blockers and steroids may also be advised.
Systemic mastocytosis is a rare yet morbid hematological disorder. This case highlights the need for careful diagnostic planning to prevent the sequelae of life‐threatening mediator‐related events.
To cite this abstract:Nagasaka M, Nigo M, Ban H, Azizi E, Burger A, Shapira I. Systemic Mastocytosis — an Introduction to a Rare Hematological Disorder Requiring Careful Diagnostic Planning. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 426. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/systemic-mastocytosis-an-introduction-to-a-rare-hematological-disorder-requiring-careful-diagnostic-planning/. Accessed March 28, 2020.