Parotid Swelling Unmasked: Tuberculosis Masquerading as Pleomorphic Adenoma

Abstract

Introduction: Tuberculosis involving the parotid gland is an exceedingly rare manifestation, representing less than 0.1% of all tubercular infections. Its clinical and radiological resemblance to benign parotid tumors, especially pleomorphic adenoma, often leads to diagnostic confusion and unnecessary surgical interventions.  

Aims & Objectives: This case report aims to describe an unusual presentation of parotid tuberculosis initially misdiagnosed as pleomorphic adenoma, to highlight the diagnostic utility of fine-needle aspiration cytology (FNAC) and Ziehl–Neelsen staining, and to emphasize the importance of clinical suspicion in endemic regions.

Case Presentation: A 62-year-old male presented with a slow-growing, painless swelling in the right parotid region of several months’ duration, associated with intermittent low-grade fever. Clinical examination revealed a firm, ill-defined swelling below the pinna. Ultrasonography showed a heterogeneous lobulated lesion in the superficial lobe of the parotid, raising suspicion of pleomorphic adenoma. FNAC and Ziehl–Neelsen staining were performed to establish the diagnosis.

Results: Cytological examination revealed epithelioid cell granulomas, lymphohistiocytic clusters, and necrosis. Ziehl–Neelsen staining demonstrated acid-fast bacilli with 3+ positivity, confirming the diagnosis of parotid tuberculosis. The patient was started on standard anti-tubercular therapy (ATT) as per national guidelines. Remarkable clinical improvement with significant regression of the swelling was observed within weeks of therapy, avoiding unnecessary surgical excision.  

Conclusion: Parotid tuberculosis, though rare, should be considered as a differential diagnosis in patients presenting with parotid swelling, especially in tuberculosis-endemic regions. Its clinical and imaging resemblance to pleomorphic adenoma makes diagnosis challenging. FNAC combined with AFB staining remains the cornerstone for diagnosis, allowing prompt initiation of medical management and preventing unwarranted surgical interventions. A high index of suspicion, supported by cytopathological evidence, is essential for timely recognition and treatment.

REFERENCES:

1. Rodriguez-Takeuchi SY, Renjifo ME, Medina FJ. Extrapulmonary tuberculosis: pathophysiology and imaging findings. Radiographics. 2019;39(7):2023-2037. https://doi.org/10.1148/rg.2019190109
2. Popescu MR, Pleşea IE, Olaru M, Strâmbu IR, Fronie AI, Petrescu IO, et al. Morphological aspects in tuberculosis of the oral cavity: our experience and an attempt to review the literature. Rom J Morphol Embryol. 2015;56(3):967-987.
3. Rocha EL, Pedrassa BC, Bormann RL, Kierszenbaum ML, Torres LR, D'Ippolito G. Abdominal tuberculosis: a radiological review with emphasis on computed tomography and magnetic resonance imaging findings. Radiol Bras. 2015;48(3):181-191. https://doi.org/10.1590/0100-3984.2013.1801
4. Hu SS, Wei QC, Wu Y, Li XN, Liu FJ, Wang B. Treatment course of cavitary pulmonary tuberculosis combined with tuberculosis in a parotid Warthin's tumor: a case report and literature review. BMC Infect Dis. 2024;24(1):1298. https://doi.org/10.1186/s12879-024-10193-7
5. Momin MB, Amitha G, Aluri A, S S. Comparative analysis of GeneXpert assay in addition to Ziehl-Neelsen microscopy for detection of extrapulmonary tuberculosis in fine-needle aspiration samples. Sch J App Med Sci. 2017;5(7D):2803-2808. doi:10.36347/sjams.2017.v05i07.058.
6. Agashe VM, Johari AN, Shah M, Anjum R, Romano C, Drago L, et al. Diagnosis of osteoarticular tuberculosis: perceptions, protocols, practices, and priorities in endemic and non-endemic areas of the world-a WAIOT view. Microorganisms. 2020;8(9):1-19. https://doi.org/10.3390/microorganisms8091312
7. Devi RS, Kumar A, Singh A, Durgapal P, Kishore S, Phulware RH. Cytological diagnosis of tuberculosis. J Cytol. 2024;41(1):1-9.
8. Kim YH, Jeong WJ, Jung KY, Sung MW, Kim KH, Kim CS. Diagnosis of major salivary gland tuberculosis: experience of eight cases and review of the literature. Acta Otolaryngol. 2005;125(12):1318-1322. https://doi.org/10.1080/00016480510012246
9. Tarasova LG, Filinyuk OV. Orofacial tuberculosis: clinic, diagnosis, differential diagnosis. Tutorial. Tomsk: Siberian State Medical University. 2020:1-100.
10. Chauhan R, Sultan M, Badhe P. Primary parotid tuberculosis presenting as a malignancy: an exceptional occurrence. EMJ Radiology. 2024;9(3):138-143. https://doi.org/10.33590/emj/hnqh1996
11. Geetha JP. Role of fine needle aspiration cytology and immunochromatographic test (ICT-TB) in the diagnosis of tuberculous lymphadenopathy [dissertation]. Bengaluru: Rajiv Gandhi University of Health Sciences. 2008:1-24.
12. Baligar SS. Correlation of cytomorphologic changes at FNAC with the presence of acid-fast bacilli detected by the Ziehl–Neelsen and fluorescent stains in tuberculous lymphadenitis [dissertation]. Bengaluru: Rajiv Gandhi University of Health Sciences. 2014:1-24.
13. Anaghashree US. Outcome of patients with extrapulmonary tuberculosis on treatment with anti-tubercular therapy [dissertation]. Bengaluru: Rajiv Gandhi University of Health Sciences. 2019:1-24.
14. 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):118-122. https://doi.org/10.4103/njms.njms_34_18
15. Azeez ZF, Al-Saadi ZH, Al QK. Diagnostic approaches for sexually transmitted infections in clinical microbiology: a comprehensive review. Infection. 2024;10(2):1-16. https://doi.org/10.55640/ijmsdh-10-02-07