ALK and Histiocytosis: We report a case that expanded the spectrum of a rare disease and present a novel diagnostic trap for both pathologists and clinicians.<h4>Methods</h4>Histopathological, immunohistochemical (CD68, CD163, ALK), and molecular (FISH) analyses were performed on a right adrenal tumor from an 81-year-old male.<h4>Results</h4>The tumor was diagnosed as ALK-positive histiocytosis.