Clinically suspected granulomatous skin lesions on the face: A prospective clinico-pathological correlation study of...

Background Granulomatous skin lesions pose a diagnostic challenge due to overlapping clinical and histopathological features. Objectives To describe the clinical and histopathological features of facial granulomatous lesions and their clinical mimics, and evaluate the utility of clinico-pathological correlation in making the final diagnosis. Methods This was a cross-sectional study including 77 patients with clinically suspected granulomatous skin lesions on the face. Diagnosis was based on clinico-pathological features, and where required, ancillary investigations and/or therapeutic trial. Clinico-pathological correlation was classified as concordant, discordant, or non-contributory. Results A definitive diagnosis could be made in 70 (91%) cases - 58 (75%) based on clinico-pathological correlation and 12 (16%) on additional ancillary investigations and/or therapeutic trial, while 7 (9%) cases remained undiagnosed. The 70 diagnosed cases included 60 (86%) granulomatous and 10 (14%) non-granulomatous dermatoses. Orofacial granulomatosis (n=25), leprosy (n=15), and sarcoidosis (n=10) accounted for >80% of granulomatous lesions, while pseudolymphoma and lupus erythematosus (4 cases each) were the most common non-granulomatous diseases. Histopathology was concordant with clinical diagnosis in 57 (74%) cases, discordant in 8 (10%) cases, and non-contributory in 12 (16%) cases. In cases with two or more clinical differential diagnoses (n=35), histopathology aided the diagnostic decision process in 20 (57%) cases. Clinically, swellings and lip involvement favoured granulomatous lesions, while follicular plugging and nose involvement were more common in non-granulomatous lesions. Among granulomatous lesions, macules, plaques, and large (>5 cm) plaques, scaling, and forehead and nose/peri-nasal area involvement were more common in the infectious group, while swelling and lip involvement were more common in the non-infectious group (p<0.05). Limitations A relatively small number of non-granulomatous and some granulomatous dermatoses Conclusion Granulomatous skin lesions on the face can be a diagnostic dilemma with varied clinical morphologies and histological patterns. A small subset remains undiagnosed despite comprehensive evaluation. Though not definitive in all cases, histopathology remains a valuable diagnostic tool, particularly in clinically challenging cases. Diagnostic yield can be increased by integrating ancillary investigations and therapeutic trial.