Introduction: Melanocytic nevi are neoplasms resulting from the proliferation of melanocytes. Diagnosis of melanocytic tumours can be tricky, considering two factors,to diagnose origin and determination of its benign or malignant nature. Visualisation of melanin or other pigments are non specific with Hematoxylin and Eosin (H&E) staining and specific with Melan-A Immunohistochemistry (IHC). Intensity and pattern of these reactions shows marked variability in different melanocytic lesions. Aim: To study the intensity and pattern of Melan-A expression in various pigmented melanocytic nevi and to understand its utility to differentiate close mimickers. Materials and Methods: A cross-sectional study of 50 lesions (45 cases and 5 controls) was conducted in the Department of Pathology of Dr. B.R. Ambedkar Medical College (tertiary hospital), Bengaluru, Karnataka, India, between September 2020 to October 2021. The skin biopsies received were fixed in formalin and paraffin embedded. Sections were stained with H&E and Melan-A IHC marker, using A103 antibody and a high temperature antigen retrieval was performed. Pattern and intensity of Melan-A expression were studied and its evaluation was done with normal skin (control). Results: Melan-A showed varied intensity (+ weak; ++ moderate; +++ strong), pattern (patchy, diffuse), distribution and on various pigmented melanocytic lesions and mimickers were analysed. Dermal nevi (18) showed +++ diffuse pattern in dermis and two cases showed ++ moderate and patchy staining. Five cases of Compound nevi showed ++ intensity, diffuse pattern in Dermoepidermal Junction (DEJ) and dermis, Deep penetrating nevi (in one case) +++ intensity and diffuse pattern in DEJ, Dermis. Two cases of pigmented Basal Cell Carcinoma (BCC) showed + intensity and no definitive pattern in dermis. Four cases in fibrohistiocytic lesions and Malignant Peripheral Nerve Sheath Tumour (MPNST) shows negative Melan-A. In control melanocytes show dendritic pattern of staining and melanophages were negative. Conclusion: Melan-A is specific melanocytic marker as it stains only melanocytic lineage and no other cell types in background thus it is a marker of histogenesis instead of malignancy indicator. It highlights important architectural features and confirms the origin of lesions thus aiding the pathologist towards accurate diagnosis and differentiates from close mimickers.

Several clinicopathological illnesses impact the testis and paratesticular area, which are divided into non-neoplastic and neoplastic diseases. Despite the availability of imaging and tumor marker testing, histopathological examination is the primary method for diagnosing testicular lesions. Common indications of orchidectomy for non-neoplastic lesions are cryptorchidism, epididymitis and testicular torsion. Few non- neoplastic lesions present as mimickers of neoplasm with commonest being granulomatous orchitis and AFB positivity detected only in 2.1% of cases with bilateral presentation being rarest. We report here a series of six cases of epididymo-orchitis to discuss the histopathological spectrum with varied etiologies. Age of the patients ranged between 33-65yr old males. Amongst six cases, two of them were clinically and radiologically suspected as neoplastic lesions, which were histopathologically diagnosed as granulomatous epididymo-orchitis with one among it showing strong positivity for AFB, and two cases as testicular torsion with orchitis and one of the case was diagnosed as cryptorchid testis with foci of atypical germ cell and last case was reported as mild non-specific orchitis, for surgical castration. In this study, we also noted unilateral presentation being the commonest, specifically of Right side. Knowledge of histopathological spectrum of epididymo-orchitis is of prime importance to detect underlying specific etiology for targeted therapy and prevent undue orchidectomy.In this study, two cases which were clinically suspected as neoplastic lesions, were confirmed as granulomatous epididymo-orchitis on histopathological examination with one case showing strong AFB positivity.In this study, we noted late presentation (5th decade) of cryptorchidism with some atypical germ cells which are forerunner of malignancy.