MILIARY METASTATIC ADENOCARCINOMA

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Miliary opacities are defined as innumerable 1- 4mm pulmonary nodules scattered throughout the lung fields. Differential for miliary pattern is wide including tuberculosis, fungal infection and distinct organ metastasis. We present a case of a 37 year old male with miliary pattern seen on the chest radiograph and CT scan with ostial lesion in his L2 vertebrae, who was initially thought to have miliary TB with Pott's disease later diagnosed with primary adenocarcinoma of the lung with spinal, brain and calvarium metastasis. CASE PRESENTATION: A 37-year-old male with no significant medical history presented to the ED with 2 months of lower back pain. He endorsed shortness of breath and 40 pound unintentional weight loss over 3 months. He was incarcerated 5 years ago at which time his PPD was negative.Chest x-ray showed diffuse bilateral infiltrates with micronodular pattern. Following this, CT scan was obtained to evaluate for lower back pain which showed pathological compression deformity in L2 and innumerable pulmonary nodules consistent with miliary pattern and also showed left upper lobe lung mass.Given his history of incarceration, weight loss, shortness of breath and deformity in his lumbar vertebra, miliary tuberculosis and Potts disease was considered. QuantiFERON gold and AFB sputum were obtained. After AFB x3 negative on sputum studies it was decided to proceed with bronchoscopy with bronchoalveolar lavage (BAL).Lymph node biopsies and BAL pathology reports came back positive for adenocarcinoma. Upon further investigation with MRI of the brain and the spine it was also noted that the patient had Cavalier metastasis, left frontal lobe metastasis and numerous enhancing bone lesions in lumbar and sacral spine with osseous metastasis.Oncology and radiation oncology were consulted and he was started on stereotactic radiation therapy to the left frontal lobe metastasis as well as a right calvarial metastasis and systemic chemotherapy and immunotherapy. DISCUSSION: Miliary opacities are seen in a wide array of conditions including infectious etiologies like miliary TB, histoplasmosis, other fungal infections and noninfectious etiologies including miliary metastasis from thyroid, renal, breast carcinomas, metastatic melanoma. There has also been documentation of miliary patterns seen in Langerhans' cell histiocytosis, hypersensitivity pneumonitis and a few cases of primary pulmonary lung cancers.History is a key component in diagnosis especially for patients coming from areas and populations where TB and other infectious disease are prevalent. Once infectious etiologies have been ruled out approach to rule out malignancies and metastasis should be perused. CONCLUSIONS: It is impossible to distinguish between infectious etiologies and malignancies solely based on CT scan in patient with miliary pattern, hence when definitive diagnosis is uncertain, tissue diagnosis should be perused. REFERENCE #1: Khan D, Danjuma M, Saddique M, U, Murshed K, A, H, Yassin M, A: Adenocarcinoma of the Lung Mimicking Miliary Tuberculosis. Case Rep Oncol 2020;13:139-144. doi: 10.1159/000505685 DISCLOSURES: No relevant relationships by Sarasi Jayaratne, source=Web Response No relevant relationships by Gaurang Prabhu, source=Web Response No relevant relationships by Gaurav Prabhu, source=Web Response