A rare case of hepatoid adenocarcinoma of the lung initially presenting as a painful skin nodule

Hepatoid adenocarcinoma of the lung (HAL) is a rare and aggressive subtype of pulmonary adenocarcinoma, with cutaneous metastasis being an uncommon clinical manifestation. A 49-year-old male presented with a painful, nodular skin lesion on the upper back. Histopathological examination confirmed it as a cutaneous metastasis of HAL. Subsequent imaging revealed a large primary tumor in the left lung and widespread metastatic disease. Remarkably, the skin lesion was the initial and only presenting feature. This case illustrates the variable clinical presentation of HAL and underscores the need for thorough evaluation of atypical skin lesions.