To study the differentials of suppurative lymphadenitis by FNAC and their evaluation by Z.N. staining, CB-NAAT, fluorescent microscopy, fungal and bacterial cultures

Abstract

Introduction: Suppurative lymphadenitis is most commonly unilateral in presentation. It is caused due to transportation of invading microorganisms (initially penetrating from mucosa or skin of the head or neck most commonly) to afferent lymph nodes. The most common bacterial causes of suppurative lymphadenitis are Staphylococcus aureus and Streptococcus pyogenes, accounting for between 40% and 89% of cases.AIM: To study the cytomorphological features in fine needle aspiration smears from patients suspected of having suppurative lymphadenitis and to study the differentials of suppurative lymphadenitis by FNAC and their evaluation by Z.N. staining, CB-NAAT, fluorescent microscopy, fungal and bacterial cultures so as to know the exact cause of suppurative lymphadenitis.Material and Methods: The present study was conducted in 50 patients of clinically suspected cases of suppurative lymphadenitis. Fine needle aspirations were performed and smears from the aspirates were processed for routine cytology (H&E, MGG) N, the conventional ZN method, fluorescent method, CBNAAT, bacterial and fungal culture for evaluation.Results: Z.N. positivity was seen in 34.14% while with fluorescent stain positivity was increased up to 60.97% and was increased up to 78.05% with CB-NAAT. Fluorescent stain positivity was seen in 60.97% while with CB-NAAT positivity was increased to 78.05%. Out of 9 cases of with bacterial etiology, only 5 cases were positive on bacterial culture. 3 cases showed MRSA and two cases showed Streptococcus pyogenes. No case of fungal lymphadenitis was identified in our study as all the cases were negative on PAS staining and fungal culture. Conclusion: Though cytomorphological appearance and Z.N. staining are commonly used in developing countries as they are economical and convenient alternative to open biopsy of lymph nodes but fluorescent method proves to be more sensitive technique than the Z.N. CB-NAAT proves to be more sensitive than both Z.N. and fluorescent staining for those patients which show cytomorphological appearance of TB. Patients with high risk of tuberculosis in whom AFB smear examination is usually negative are most likely to be benefited from CB-NAAT. Hence for the differentials of suppurative lymphadenitis cytomorphological examination along with various other ancillary techniques (methods) has more diagnostic value.