Adult-Onset Acquired Ichthyosis Revealing an Underlying Colon Adenocarcinoma.

Acquired ichthyosis is an uncommon dermatologic disorder that presents in adulthood and is often associated with systemic conditions, including malignancies. We report the case of a 38-year-old male patient who developed diffuse scaling characterized by rhomboidal, fish-like scales predominantly affecting the trunk and limb extensors, with sparing of the flexures, palms, and soles. Initial therapeutic interventions with emollients and corticosteroids were unsuccessful. A skin biopsy confirmed the diagnosis of acquired ichthyosis, and subsequent diagnostic imaging revealed an underlying colon adenocarcinoma. Notably, the patient's family history was significant for his mother's colon adenocarcinoma, suggesting a potential genetic predisposition. This case highlights the critical importance of conducting a comprehensive diagnostic evaluation for underlying malignancies upon the diagnosis of acquired ichthyosis, particularly in patients with pertinent familial cancer histories. Although the patient was lost to follow-up, this case underscores the role of acquired ichthyosis as a potential paraneoplastic marker, emphasizing the need for early detection and management of associated malignancies.