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A4040 - An Atypical Bronchopulmonary Carcinoid Tumor Manifesting as Abdominal Cramping
Author Block: N. Kaur1, M. Kantor1, Y. Orive1, D. Bonilla2, L. Bosch3; 1Internal Medicine, Kendall Regional Medical Center, Miami, FL, United States, 2Pulmonary and Critical Care, Kendall Regional Medical Center, Miami, FL, United States, 3Pulmonary Medicine, Kendall Regional Medical Center, Miami, FL, United States.
Lung neuroendocrine tumors (NETs) are a group of pulmonary neoplasms that comprise approximately 25% of all lung malignancies. Of these foregut-derived masses, bronchopulmonary carcinoid tumors are the most rare, accounting for less than 1% of all lung cancers and with global incidence rates of 0.2 to 2.0 per 100,000 population per year. Data reveals a higher prevalence amongst women than men and in whites than blacks. Generally, these neoplasms are well-differentiated, indolent, and hypervascular. Due partially to their rarity and in part to the benign nature of a patient’s complaints, carcinoid tumors may either go undiagnosed or diagnosed incidentally.
A 38 year-old Hispanic female presented to our institution with complaints of cramping, intermittent, right upper quadrant abdominal pain of one week’s duration. While an abdominal ultrasound was negative for abnormalities, a CT scan of the abdomen revealed a 14 mm enhancing lesion in the inferior aspect of the right lobe of the liver as well as multiple pulmonary nodules at bilateral lung bases. Subsequently, a high-resolution CT scan of the thorax was performed, demonstrating the presence of innumerable pulmonary parenchymal nodules, primarily scattered along the periphery of both lungs, with the largest being 12 mm. Patient underwent a CT-guided transthoracic needle aspiration of the largest nodule, after which she developed intraparenchymal hemorrhage at the site of the biopsy, requiring early termination upon retrieval of tissue samples. The core needle biopsy was sent for histopathologic diagnosis, revealing a monomorphic epithelioid neoplasm with a neuroendocrine appearance and central necrosis. Immunohistochemical staining confirmed an atypical pulmonary carcinoid tumor with positive staining patterns for chromogranin A and synaptophysin but negative for other cytoplasmic proteins found in primary lung cancers and metastatic lesions, including thyroid transcription factor-1 (TTF-1), estrogen receptors, and inhibin.
Many patients with bronchopulmonary carcinoid tumors do not present with symptoms typical of carcinoid syndrome, particularly cases in which tumors are located peripherally, thereby demanding a higher index of clinical suspicion. Patients are either asymptomatic or manifest nonspecifically, leading to sole symptomatic management and further delays in diagnosis. Radiographic evidence of potentially hypervascular lesions that appear to be isolated to the liver and not favoring features consistent with an adenoma, should incite a further work-up of carcinoid tumor, especially due to it’s strong propensity to metastasize to the liver. While arteriovenous malformations may present similarly and hemorrhage can be expected in both diseases, histopathology will further confirm the presence of a NET.