SESSION TITLE: Interstitial Lung Disease Student/Resident Case Report Posters I
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Diffuse, bilateral, reticulonodular infiltrates are often concerning for pulmonary infection, such as miliary tuberculosis (TB), or metastatic disease from hematogenous spreading. Primary pulmonary tumors, whether benign or malignant, are rarely suspected as the cause of this radiologic finding.
CASE PRESENTATION: A 66 year old female with a history of remote thyroid papillary carcinoma treated with parathyroidectomy and thyroidectomy initially presents to an ER with chest pain. Her electrocardiogram is benign and laboratory results include WBC 6.83, Hgb 14.4, sodium 139, ESR 8, CRP 9.1, and normal cardiac enzymes. Given suspicion for a pulmonary embolus, a CT chest reveals a bilateral, diffuse, miliary-type micronodular pattern in the lung parenchyma concerning for TB or metastases (figure 1). The patient has no recent history of fever, weight loss, hemoptysis or shortness of breath, but does support new night sweats. She denies any recent TB exposure and her QuantiFERON TB Gold test is negative. The patient is then referred to pulmonology clinic and a bronchoscopy with transbronchial lung biopsy is performed. Fungal and Acid-Fast-Bacilli cultures are negative on both the bronchoalveolar lavage and biopsy samples. The pathology report from the biopsy is significant for a pulmonary meningothelial-like lesion, also called “chemodectoma”.
DISCUSSION: Minute pulmonary meningothelial-like nodules (MPMN) were first described as nests of epitheliod cells and labeled as pulmonary chemodectomas in 1960 (1). However, MPMNs lacked the features of neuroendocrine cells that would be consistent with chemodectomas and were later re-classified as meningothelial-like cells (2). They are most often discovered as incidental findings on autopsies and are usually noted in a single lobe of the lung or at most in a unilateral lung. Rarely, MPMN are identified in a diffuse, bilateral pattern. Miliary pulmonary infiltrates related to a chemodectoma were first described in 1973, when a case was reported with metastatic carotid body tumor spread (3). However, only a handful of cases have been reported describing a diffuse, miliary pattern for MPMN presentation since that time.
CONCLUSIONS: A radiologic finding of a diffuse miliary-type reticulonodular pattern on a chest CT may not necessarily be secondary to an infectious source or metastatic disease. It is always essential to correlate the radiographic pattern with the clinical presentation in which a benign process could account for an incidental finding.
Reference #1: Korn D et al. Multiple minute pulmonary tumors resembling chemodectomas. Am J Pathol. 1960;37:641-672.
Reference #2: Gaffey MJ, Mills SE, Askin FB. Minute pulmonary meningothelial-like nodules: a clinicopathologic study of so-called minute pulmonary chemodectoma. Am J Surg Pathol. 1988;12:167-175.
Reference #3: Tu H, Bottomley RH. Malignant chemodectoma presenting as military pulmonary infiltrate. Cancer. 1974;33:244-249.
DISCLOSURE: The following authors have nothing to disclose: Sharjeel Hooda, Danai Khemasuwan, Atul Mehta
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