Pseudosarcomatous fibromatosis

This code represents a benign, locally aggressive soft tissue proliferation characterized by spindle cell growth that can mimic a sarcoma histologically. It is a reactive process, often occurring after trauma or in association with certain inflammatory conditions, and does not metastasize.

Use this code for documented cases of pseudosarcomatous fibromatosis, also known as nodular fasciitis. This diagnosis is typically confirmed by biopsy and histopathological examination, distinguishing it from malignant soft tissue tumors. Documentation should clearly state the benign nature of the lesion.

• Ensure pathology reports confirm the benign diagnosis of pseudosarcomatous fibromatosis to avoid miscoding as a malignant neoplasm.
• Do not confuse with true sarcomas (e.g., fibrosarcoma) which are malignant and coded differently.
• Consider an additional code for the anatomical site if specified and relevant (e.g., M79.5 for pain in limb, M79.6 for other specified pain).