Alterations in the skin of the perianal region may result from inflammatory dermatoses (such as psoriasis, lichen planus, lichen sclerosis, etc.) as well as from various infectious, parasitic, autoimmune, hereditary, and oncological conditions. The similarity of clinical signs complicates the diagnostic process in patients, resulting in delayed therapy initiation and diminished efficacy. Prompt diagnosis is particularly significant in instances of skin metastases from malignant neoplasms. Typically, it indicates a pervasive process and the existence of secondary lesions affecting not only the skin but also the lymph nodes and internal organs. Although skin metastases are prevalent in melanoma and several solid tumors, such as breast and lung cancer, they are exceedingly rare in the context of rectal cancer. Besides, verifying secondary skin lesions may be challenging despite a recognized primary focus due to potential immunodeficiency, chemotherapeutic agents’ cutaneous toxicity, and radiation-induced responses and damage. Consequently, the differential diagnosis of skin metastases presents a considerable challenge for clinicians. We describe a clinical case of skin metastasis from rectal adenocarcinoma in the perianal region, occurring during the complex treatment of the primary disease.