INTRODUCTION: Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a rare histiocytosis of unknown etiology that typically involves the cervical lymph nodes. Extranodal involvement can occur in any organ system in up to 30-40% of cases, however, exclusively extranodal involvement of the lung has not been reported. We report a case of extranodal Rosai-Dorfman disease which invaded the left lower lobe bronchus and abutted the left pulmonary artery in a previously healthy 21-year-old man presenting with hemoptysis.
CASE PRESENTATION: A 21-year-old Mexican man presented to the emergency department complaining a one day history of hemoptysis, with one month of general malaise, subjective fever, and 3 days of nausea and vomiting prior to presentation. Vital signs were unremarkable. Physical exam revealed significant inspiratory stridor with asymmetrical chest expansion and bright red blood in the oropharynx without evidence of epistaxis. Laboratory data were unremarkable with a normal range white blood cell count and hemglobin of 16 mg/dL. Chest radiography suggested a subtle opacity within the medial left lung base. A CT scan of the chest revealed a 4.5 cm x 4.5 cm left hilar mass encasing portions of the left pulmonary arterial and pulmonary venous system as well as the left main stem bronchus without significant adenopathy. The patient was admitted to the intensive care unit and underwent emergent fiberoptic bronchoscopy, which revealed hemorrhage within the narrowed left lower lobe bronchus. No endobronchial mass was seen, however, visualization was compromised by continued bleeding without an identifiable source. Thoracic surgery was consulted, and an urgent complete left pneumonectomy was performed. Gross pathologic inspection of the mass revealed a 3.5 x 3.4 x 3.2 cm peribronchial mass invading the superior division of the left inferior lobe with abutment but no invasion of the left pulmonary artery. Microscopic review revealed atypical foamy macrophages with enlarged nuclei which appeared to be engulfing lymphocytes. Immunostaining revealed findings consistent with a diagnosis of extranodal Rosai-Dorfman disease.
DISCUSSIONS: Rosai-Dorfman disease is a histiocytosis typically characterized by lymph node sinuses expanded by numerous histocytes with round, vesicular nuclei and emperipolesis. Immunohistochemistry reveals positivity for S-100 protein, CD68, and alpha-antichemotrypsin, and negativity for CD1a. Involvement of the lymph nodes of the neck, axilla, inguinal region, hilum, or mediastinum is common, and extranodal involvement is known to include the nasal cavity, oral cavity, trachea, skin, breast, and central nervous system. The prognosis of this disease is good, with a median survival of greater than 5 years after diagnosis, but death has been reported when the disease affects the vital organs (1). Intrathoracic manifestations of Rosai-Dorfman disease are more common than previously thought, found in up to 43% of cases of Rosai-Dorfman disease in one review, however, extranodal lung involvement without lymphadenopathy has not been reported (1). Furthermore, involvement of the great vessels has only been reported in one other case report (2).
CONCLUSION: Our patient was diagnosed with extranodal Rosai-Dorfman disease which abutted the pulmonary artery and invaded the left lower lobe bronchus leading to airway compromise and hemoptysis. Upon review of the literature, this is only the second case of Rosai-Dorfman disease reported involving the great vessels, and the first reported exclusively extranodal presentation of the disease in the lung.
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