Computed Tomography Features of Parotid Tuberculosis

A 27-year-old man presented with enlargement of the left cervical region, fever, and weight loss for the past month. Physical examination revealed left cervical lymph node enlargement with skin fistulization. Hemogram and chest computed tomography (CT) findings were normal. Neck CT revealed a mass with heterogeneous contrast enhancement and central necrosis in the left parotid, with fistulization to the skin and lymph node enlargement (Figure 1). Analysis of a fine-needle aspiration sample yielded a positive GeneXpert^® MTB/RIF assay result, suggesting tuberculosis. Serological analysis was negative for human immunodeficiency virus. Culture was positive for Mycobacterium tuberculosis. The patient was treated with rifampicin, isoniazid, pyrazinamide, and ethambutol.

FIGURE 1:
Primary parotid tuberculosis. Axial (A) and coronal (B) neck CT images showing an expansive lesion with heterogeneous enhancement and a central area of necrosis in the superficial lobe of the left parotid gland (thick arrow in A, arrow in B). The main parotid duct had a normal caliber. Sialolithiasis was absent. Also note the skin fistulization of the lesion (thin arrow in A). Cervical lymph node enlargement was present ipsilateral to the lesion, in the coronal plane (arrow in C).

Tuberculosis rarely involves the salivary glands because antibacterial activity and continuous saliva flow prevent the accumulation of the bacillus. Among the salivary glands, the parotid glands are most commonly involved because of their slower saliva flow¹. A primary pulmonary focus and hematogenous and/or lymphatic dissemination usually characterizes parotid involvement but dissemination via the parotid duct from an oral-cavity or lymph-node focus can also occur². CT usually shows a lobulated heterogeneously enhancing mass, associated with lymph-node enlargement. Primary neoplasms and other infectious diseases, such as other bacterial and fungal infections, are important differential diagnoses^1,3. In the Brazilian public health system, the GeneXpert^® MTB/RIF assay is an important tool for diagnosing tuberculosis. It detects M. tuberculosis genetic material and rifampicin resistance within two hours⁴. Therefore, tuberculosis should be considered in cases presenting with parotid lesions to avoid unnecessary treatment and procedures.

ACKNOWLEDGMENTS:

none.

REFERENCES

• ¹
  Maurya MK, Kumar S, Singh HP, Verma A. Tuberculous parotitis: A series of eight cases and review of literature. Natl J Maxillofac Surg. 2019;10(1):118-22. Available from: 10.4103/njms.NJMS_34_18
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  de Lima TM, Belotti NCU, Nardi SMT, Pedro HSP. Teste rápido molecular GeneXpert MTB/RIF para diagnóstico da tuberculose. Rev Pan-Amaz Saude 2017; 8(2):67-78. Available from: 10.5123/S2176-62232017000200008
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• Financial Support: None.

Publication Dates

• Publication in this collection
  30 Oct 2023
• Date of issue
  2023

History

• Received
  20 Sept 2023
• Accepted
  09 Oct 2023