Final answer:
Fibrous xanthoma can occur in both the upper and lower extremities, as well as other areas of the body. It is associated with conditions like pseudoxanthoma elasticum and systemic lupus erythematosus.
Step-by-step explanation:
Fibrous xanthoma is a type of skin lesion that can occur in both the upper and lower extremities. It is typically characterized by a large brown spot on the skin with darker specks, and may have an irregular border with red, white, blue, or blue-black areas. The lesions can also be found on the palms, soles, fingertips, toes, or mucous membranes.
Fibrous xanthoma is often associated with conditions such as pseudoxanthoma elasticum and systemic lupus erythematosus. Pseudoxanthoma elasticum is a hereditary disease that affects the skin, eyes, and cardiovascular system, while systemic lupus erythematosus is a chronic inflammatory disorder. These conditions can contribute to the development of fibrous xanthoma.
In summary, fibrous xanthoma can be found in both the upper and lower extremities, as well as other areas of the body. It is important to consult a healthcare professional for proper diagnosis and treatment.