Utility of FNAC in Dermatological Manifestations of Metastatic Cancer with the Review of the Literature

OBJECTIVES: Cutaneous metastasis (CM) though rare, indicates a terminal event in any malignancy and has a grave outcome. The present study reiterates the role of fine needle aspiration cytology (FNAC) in the diagnosis of metastatic cutaneous nodules. MATERIALS AND METHODS: From 2015 to 2017, the department received 22,000 cases for FNAC. Among these cases, aspirations from the skin and subcutaneous region were performed on 6,083 cases. After excluding primary tumors of skin/subcutis, 25 cases on cytology were suggestive of metastasis. Clinicoradiological and histopathological profiles in these cases were reviewed. RESULTS: Among these 25 patients, the male to female ratio was 1:1.09 (F, 12; M, 13) in the age group of 18–72 years. Most common primary malignancy in females was of breast and in males was gall bladder. The most common manifestation was a palpable skin nodule, with the abdominal wall being the predominant site. The most common diagnosis, on cytology, was metastatic adenocarcinoma. CONCLUSION: FNAC is a minimally invasive method, which aides in prompt detection and appropriate management of cases presenting with skin nodules and clinically unsuspected of malignancy. Whereas in known primary tumor, it indicates dismal prognosis by diagnosing CM; in cases with unknown primaries, cytomorphology in conjunction with clinicoradiological findings often gives a clue to the possible primary site.