Myositis ossificans progressiva, unspecified toe(s)

This code represents a rare, severe genetic disorder characterized by progressive heterotopic ossification (bone formation in soft tissues) affecting the unspecified toe(s). The condition leads to debilitating stiffness and loss of mobility as muscle and connective tissues are gradually replaced by bone.

Apply this code when documentation explicitly states a diagnosis of myositis ossificans progressiva affecting an unspecified toe or toes. This diagnosis is typically made based on clinical presentation, genetic testing, and imaging studies confirming heterotopic ossification.

• Ensure documentation specifies "progressiva" to differentiate from myositis ossificans traumatica.
• Avoid using this code if the specific toe (e.g., great toe, other toe) is identified; use the more specific M61.171-M61.178 codes.
• Consider sequencing this code after a code for the underlying genetic disorder, if applicable and documented.