SESSION TYPE: Cardiovascular Cases
PRESENTED ON: Wednesday, October 24, 2012 at 11:15 AM - 12:30 PM
INTRODUCTION: CT angiographic diagnosis of pulmonary thromboembolism (PTE) is based on the identification of one or more filling defects in the pulmonary arterial tree. However, not all such filling defects are due to PTE. This report highlights a misdiagnosis resulting in a fatal outcome from an extremely rare mimic of PTE.
CASE PRESENTATION: A 61-year-old woman with a history of HIV infection (CD4=552) presented with recurrent syncopal episodes over an 18 month period. Previous workup had revealed a central pulmonary artery (PA) filling defect with total occlusion of the right PA. A presumptive diagnosis of PTE had been made, treated with oral anticoagulation. Repeat imaging showed progression of the central filling defect, now extending into the main and left PA (Figure 1). A right heart catheterization was performed to obtain tissue diagnosis of the suspected PA mass. However, severe hemodynamic instability ensued after attempted biopsy of the mass. The patient died 2 days later due to right heart failure and refractory shock. Autopsy showed a 6.4 x 3.2 x 3.0 cm tan well-circumscribed lesion within the pulmonary trunk, extending into the right and left pulmonary arteries. Histopathology and immunehistochemistry confirmed a diagnosis of extranodal Rosai-Dorfman Disease (RDD).
DISCUSSION: RDD, also known as sinus histiocytosis with massive lymphadenopathy, is a benign histiocyte proliferation of unknown etiology1. RDD may present as (a) nodal disease, with predominantly cervical lymph node enlargement; or (b) extranodal form, which may involve almost any other organ-system in the body. The histologic hallmark of the disease is the engulfment of intact lymphocytes and plasma cells by histiocytes, a finding known as emperipolesis (Figure 2). The histiocytes stain positive for S-100 and CD68, but negative for CD1a. Treatment depends on the site of involvement and the nature and severity of accompanying clinical manifestations. Chemotherapy, radiation and surgical debulking have been used with varying results.
CONCLUSIONS: A PA mass due to RDD is an extremely uncommon entity. Its clinical presentation and CT angiographic appearance may mimic PTE. To our knowledge, the present report is the first instance of RDD presenting as a central pulmonary artery occlusion in an HIV-infected patient, and only the second report overall of RDD presenting as an intraluminal PA mass2.
1) Rosai J, Dorfman RF. Sinus histiocytosis with massive lymphadenopathy. A newly recognized benign clinicopathological entity. Arch Pathol. 1969;87(1):63-70.
2) Walters DM, Dunnington GH, Dustin SM et al. Rosai-Dorfman disease presenting as a pulmonary artery mass. Ann Thorac Surg. 2010;89(1):300-302.
DISCLOSURE: The following authors have nothing to disclose: Tayyab Rehman, Kelley Sherling, William Newman, Stephen Kantrow, Bennett deBoisblanc
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