Merkel Cell Hyperplasia Versus Intraepidermal Merkel Cell Carcinoma: A Comparative Study of 2 Cases.

ABSTRACT: Intraepidermal Merkel cell hyperplasia and Merkel cell carcinoma represent 2 histologically similar-appearing diagnoses with significant differences regarding prognosis and management. We present 1 case of each diagnosis to highlight characteristic histopathologic and immunohistochemical features. Our case of Merkel cell hyperplasia was identified by its small intraepidermal nest of monomorphic cells without atypia or mitoses, which demonstrated cytoplasmic, rather than perinuclear dot, patterning on CK20 staining. This can be contrasted with our case of intraepidermal Merkel cell carcinoma, which, despite a lack of dermal extension, demonstrated large nests of pleomorphic cells with frequent mitoses and apoptoses. The diagnosis was further confirmed by immunohistochemistry because CK20 staining showed classic perinuclear dot patterning. By presenting both diagnoses in parallel, this comparison aims to underscore crucial histopathologic and immunohistochemical similarities and differences.

A retrospective review of the dermatologic manifestations of chronic arsenic poisoning in the Philippines.

BACKGROUND: The Section of Dermatology of the University of the Philippines, Philippine General Hospital, reported a case of chronic arsenic poisoning from a community in Luzon island to the Department of Health resulting in the conduct of two health and environmental assessment missions in December 2014. OBJECTIVE: To describe the demographic profile and cutaneous manifestations of chronic arsenic poisoning among affected residents in Luzon, Philippines. METHODS: A review of the medical records of 116 residents screened during the health assessment missions in December 2014 was conducted. RESULTS: Among the 116 residents screened, 81 (70%) had clinically confirmed arsenic keratoses and hyperpigmentation. Among them, 52 were males and 29 were females with age range of 4-82 years. Two cases of squamous cell carcinoma in situ were detected through skin biopsy. High levels of arsenic in the tap water and topsoil supported the occurrence of an epidemic of chronic arsenic poisoning. CONCLUSION: Specific dermatologic findings of arsenic keratoses and pigmentation were common among the residents screened. Significantly higher occurrence of arsenic keratoses was seen in adults.