# Many-Faced Imitator: A Case of Acinar Adenocarcinoma of the Lung Resembling Miliary Tuberculosis

## TL;DR

A case of lung cancer was initially mistaken for tuberculosis due to similar symptoms and imaging, highlighting the challenges in diagnosing 'Great Imitator' diseases.

## Contribution

The paper presents a rare case of acinar adenocarcinoma mimicking miliary tuberculosis, emphasizing diagnostic challenges in high-risk populations.

## Key findings

- The patient's clinical and radiological features initially suggested miliary tuberculosis.
- A delayed diagnosis of lung adenocarcinoma was made after an unresponsive treatment course.
- The case underscores the importance of considering malignancy in the differential diagnosis of miliary patterns.

## Abstract

The Great Imitator is a term used to describe different conditions that resemble other diseases. These include conditions such as syphilis, tuberculosis, lupus, systemic mycoses, and sarcoidosis, just to name some of which have fallen into this category of diseases that present with multi-system involvement, and a myriad of signs and symptoms that can be mistaken for other pathologic processes.

A high index of clinical suspicion is necessary to analyze the information obtained from history of present illness, physical exam, and information obtained from available tests (i.e., serology, microbiology, imaging). Additionally, physicians have to gather information from other sources, like family history, social history, epidemiology, risk factors associated with an individual's characteristics, such as ethnicity, occupational exposures, travel history, sick contacts, etc. To make this process more cumbersome, there is always the possibility of obtaining a false positive or false negative result from the tests we rely on to support a clinical diagnosis. Consequently, this leads to a missed diagnosis, with a delay in treatment, disease progression, and the need for follow-up studies.

Here, we discuss a case that presented with a clinical picture suspicious for tuberculosis. The patient belonged to a high-risk population to present this condition; radiologic imaging revealed a pattern consistent with miliary tuberculosis. Miliary opacities are defined as innumerable 1-4 mm pulmonary nodules scattered throughout the lung fields. Differential for miliary pattern is wide, including tuberculosis, fungal infection, and some neoplastic metastatic disease. In our case anti-tuberculosis regimen was initiated after microbiology results, but a torpid clinical course after initiation of these drugs led to performing more invasive interventions, which allowed us to obtain the diagnosis of adenocarcinoma of the lung.