["Dangerous" cutaneous polyp. Exophytic cutaneous myxofibrosarcoma].

Area of Science:

• Dermatopathology
• Surgical Oncology
• Medical Oncology

Background:

• Malignant skin tumors rarely present as polypoid lesions.
• Large skin tag-like presentations can obscure malignancy.
• Myxofibrosarcoma (MFS) is a common sarcoma in adults, but rarely appears as a skin tag.

Observation:

• A case is presented where a lesion clinically resembling a large skin tag was diagnosed as myxofibrosarcoma (MFS).
• The protuberant nature of the lesion led to initial misdiagnosis and shave biopsy.
• The rapid growth of the polypoid sarcoma prompted further investigation.

Findings:

• Myxofibrosarcoma (MFS), also known as myxoid malignant fibrous histiocytoma, is a common adult sarcoma.
• Clinical presentation as a large skin tag is an extremely rare manifestation of MFS.
• Histologically, MFS is characterized by a multinodular structure, mucinous stroma, and curvilinear fine vessels.

Implications:

• Unusual clinical presentations of common lesions warrant thorough investigation.
• Prompt surgical removal is indicated for rapidly growing polypoid sarcomas.
• The behavior and metastatic potential of MFS depend on tumor grade, size, depth, and local control.