Reactive lymphdenitis: an enigma

Background and Objectives: With the establishment of FNA procedure for diagnosis of lymphadenopathy, biopsies of lymph nodes have drastically reduced in number. However some clinical scenario warrants further evaluation of lymph nodes, especially as lymphomas are a heterogenous group of disorders. This case series includes five cases diagnosed on FNAC as reactive lymphadenitis where the architecture and distribution of cells played a key role in diagnosis. Methods: A total of 491 patients were diagnosed with reactive lymphadenitis during a study period. Biopsies were obtained in nine cases of reactive lymphadenitis. Result: Four cases of reactive lymphadenitis diagnosed on histopathology were also diagnosed on cytology. 5 cases reported as reactive on cytology showed features of tubercular lymphadenitis, Hodgkin’s lymphoma, Non Hodgkin’s lymphoma, metastatic deposits of squamous cell carcinoma and Castleman’s disease (one each) on histological examination. Interpretation: Positive predictive value of FNA diagnosis of reactive lymphadenitis was 77.27%. That leaves a huge number of cases where possibilities of other diagnosis can not be excluded. Architecture of the lymph node is key in the diagnosis of most lymphomas. Conclusion: Reactive lymphadenitis / a negative cytology, although reassuring for the patient, should always be interpreted with the clinical picture in mind. It does not rule out serious underlying disorder.