Clinicopathological Spectrum of Histopathologically Diagnosed Infectious Lesions in Surgical Pathology: A Retrospective Tertiary Centre Study

Background: Infectious lesions encountered in surgical pathology may mimic inflammatory or neoplastic disorders, while microbiological confirmation may be limited by low organism burden, prior treatment, sampling limitations, or nonavailability of testing. Aim: To describe the clinicopathological spectrum of infectious lesions diagnosed on histopathology and to explore their associations with demographic, anatomical, and histopathological variables, with assessment of special-stain and microbiological correlation. Methods: This retrospective observational study included 165 eligible biopsy and resection specimens identified among 13,782 surgical pathology specimens received over 18 months (January 2024–July 2025). Histopathological findings, special stain results, microbiological results where available, and clinicopathological variables were analyzed. Granulomatous inflammation without an established etiology was retained as a separate undetermined category. Exact/Monte Carlo procedures were used for sparse categorical analyses and Cramér’s V was reported as an effect-size measure. Results: Tuberculosis was the most frequent specific diagnosis (56/165, 33.9%), followed by leprosy (28/165, 17.0%), granulomatous inflammation of undetermined etiology (28/165, 17.0%), mucormycosis (18/165, 10.9%), and Helicobacter pylori gastritis (15/165, 9.1%). After separating the undetermined group, bacterial diagnoses accounted for 107/165 (64.8%), fungal diagnoses for 27/165 (16.4%), viral diagnoses for 2/165 (1.2%), and parasitic diagnoses for 1/165 (0.6%). Microbiological results were available in 106/165 cases (64.2%); 58 were positive and 48 negative, while testing was unavailable in 59 cases (35.8%). Among the 28 undetermined granulomatous cases, MTB was detected in 7 (25.0%). Significant associations were observed between diagnostic category and age group (Monte Carlo p