Metastatic Adenocarcinoma of the Lung Mimicking Miliary Tuberculosis and Pott’s Disease

Abstract

Tuberculous spondylitis (Pott’s disease) is among the frequent extra-pulmonary presentations of tuberculosis (TB). The global incidence of lung adenocarcinoma is on the rise, and it is a rare differential diagnosis of miliary shadows on chest imaging. It has a predilection to metastasize to ribs and spine in particular. There is a very close clinical and radiological resemblance in the presentation of spinal metastasis of lung cancer and Potts’s disease. It poses a diagnostic challenge to clinicians particularly in TB endemic areas to arrive at an accurate diagnosis, leading to disease progression and poor outcome. We report a 54-year-old female patient presented with constitutional symptoms of on and off fever and back pain. Her chest X-ray revealed miliary shadows, and acid-fast bacilli (AFB) sputum smear and TB polymerase chain reaction (PCR) test came negative; radiological diagnosis of tuberculous spondylitis was done on computerized tomography (CT) chest and magnetic resonance imaging (MRI) spine. Subsequent bronchoscopy and bronchoalveolar lavage (BAL) cytology showed malignant cells and CT-guided lung biopsy confirmed lung adenocarcinoma with spinal and brain metastasis. Despite being started on chemo-immunotherapy and radiotherapy her outcome was poor due to advanced metastatic disease. This case highlights the significance of considering metastatic adenocarcinoma of the lung a rare but ominous possibility in the differential diagnosis of miliary shadows on chest imaging. Early bronchoscopy and biopsy must be considered in all patients presenting with miliary pulmonary lesions and spinal lesions to make a correct diagnosis, preventing an unnecessary delay in starting proper treatment and poor outcome. It also emphasizes the importance of better understanding the different radiographic features of the two common mimics, spinal tuberculosis, and metastatic spinal tumors.

Physiotherapy Rehabilitation of a Conservatively Managed Patient With Pott’s Disease: A Case Report

“…One of the most debilitating effects of extra-pulmonary TB is Pott’s disease, often known as spinal TB [ 9 ]. Spondylitis brought on by TB is a rare condition that develops and progresses gradually [ 10 ].…”

The Diagnostic Deceiver: Radiological Pictorial Review of Tuberculosis

“…They appear as innumerable small (2–3 mm) non-caseating granulomas with random distribution in the brain with a predominance to a gray-white matter junction as a result of hematogenous dissemination [ 25 , 26 ]. Miliary TB usually strongly mimics brain metastasis [ 31 ]. Tuberculous cerebritis ( Figure 14 ) is an infection of a focal area of a brain parenchyma that appears on MRI as an area of swelling with an alteration to the signal intensity of the gyri.…”

“…They appear as innumerable small (2–3 mm) non-caseating granulomas with random distribution in the brain with a predominance to a gray-white matter junction as a result of hematogenous dissemination [ 25 , 26 ]. Miliary TB usually strongly mimics brain metastasis [ 31 ].…”

Imaging update in spinal tuberculosis

“…Among above mentioned conditions, differentiation of spinal metastasis from spinal tuberculosis is of great clinical significance. 34 Spinal tuberculosis is a benign disease, and is managed by effective antitubercular therapy, 10 whereas, spinal metastasis is a malignant disease, and surgery or chemotherapy may be optimal therapy. 35 Although, biopsy is gold standard to distinguish spinal tuberculosis from spinal metastasis, 36 diagnosis at outpatient department is often based on clinical findings, and imaging.…”

“…35 Although, biopsy is gold standard to distinguish spinal tuberculosis from spinal metastasis, 36 diagnosis at outpatient department is often based on clinical findings, and imaging. 33 Important features that help differentiate spinal metastasis from spinal tuberculosis include (i) history of malignant tumor, (ii) posterior element destruction, (iii) preserved intervertebral disc, (iv) absence of sequestrum, and (v) absence subligamentous spread 33,34 (Fig. 14).…”