Unusual sites of tuberculosis mimicking skeletal metastases: A case report

Abstract

The incidence of skeletal tuberculosis is about 1%-5% of all tuberculous infections. The most common sites are the spine, hip, knee, foot, elbow, hand, and shoulder, whereas the sternum, ribs, sternoclavicular joint, and calvaria are rarely affected. Because of the emergence of skeletal tuberculosis in therapeutic management, radiologists need to be aware of the imaging findings in pulmonary and extrapulmonary tuberculosis. Conventional X-ray plays an important role in diagnosing pulmonary and skeletal tuberculosis. Tuberculosis is known as the 'great mimicker', however, thus computed tomography and magnetic resonance imaging may provide additional details that assist the radiologist in distinguishing this tubercular infection from others. We report the case of a young male patient with skeletal tuberculosis who presented with general weakness, paraplegia, and a calvarial mass.

Keywords: Computed tomography; Extrapulmonary tuberculosis; Magnetic resonance imaging; Skeletal tuberculosis.

Fig. 1

Axial and coronal reformatted enhanced head MSCT (A,B) and axial T1 weighted images on enhanced MRI show left parietal bone destruction with soft tissue rim enhancement extending to the intracranial region, resulting in focal meningoencephalitis of the parietal lobe with slightly restricted diffusion on diffusion-weighted images (DWI) (E).

Fig. 2

Posterior vertebral destruction involving the lamina, pedicle, and the transverse and spinous processes, with a mass forming at the level of Th 5-6 that extended to the spinal canal and compressed the myelum with visible dural enhancement in axial T1 (A), coronal T1 weighted image (B), and sagittal T2 weighted image (C), Suspicion of a lung mass in axial T1 weighted image with contrast (D).

Fig. 3

Both enhanced and unenhanced thoracic MSCT show (A,B) an irregular solid mass at the right mediobasal segment, (C) multiple conglomerated lymphadenopathy from the right parabronchial to the lower paratracheal and subcarinal, (D) destruction of Th 5-6 (white arrow) and sternal bone (red arrow) with a rim-enhanced soft tissue mass. These findings are suggestive of a malignant solid lung mass with multiple bone metastases.

Fig. 4

A fine needle aspiration biopsy (FNAB) of the right lung mass using Diff-Quick staining are shown in images A and C at 200x magnification and in image B at 100x magnification, which mononuclear cells and PMNs, clusters of epithelioid histiocytes forming granulomas, and multinucleated giant cells.

Fig. 5

Histopathological evaluation of calvarial excision with haematoxylin eosin staining, with images A and B at 40x magnification showing granulomatous tissue, and C and D images at 100x magnification showing positive acid-fast bacilli staining.