Dr. Kirkby is a family medicine physician with a private practice located in Pietermaritzburg, KwaZulu-Natal, South Africa, and an editor for DynaMed (www.ebscohost.com/dynamed), a database of comprehensive updated summaries covering nearly 3,000 clinical topics. Dr. Fiesinger is a faculty member of the Conroe Medical Education Foundation Family Medicine Residency Program, Lone Star Family Health Center, Conroe, Tex.

Description
• Tumorlike lesion, but totally benign
• Form of fibromatosis
• Discrete, reactive pseudosarcomatous proliferation of fibroblasts and myofibroblasts

Also called
• Proliferating fasciitis
• Pseudosarcomatous fasciitis
• Pseudosarcomatous fibromatosis
• Infiltrative fasciitis
• Spindle cell lesion
• Proliferative fasciitis


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ICD-9 code
• 728.79 other fibromatoses of muscle, ligament, and fascia

Types
• Myxoid, fibrous, and collagenous variants

Who is most affected
• True incidence unclear
• Age 20-40 years, but can occur at any age
• Adult males and females equally affected
• Among children, boys more commonly affected

Sites of involvement
• Subcutaneous, muscular, and fascial locations
— Subcutaneous location is most common; typically well-circumscribed nodule.
— Deep fascial location; often irregular, stellate pattern
• Forearm, thigh, and upper-arm nodules
— Most common sites of presentation in young adults, particularly volar aspect of forearm
• Head and neck area common site of origination in children (ages 3 weeks to 6 years [median 18 months])

Causes
• Reactive, non-neoplastic response to injury or local inflammatory process

Pathogenesis
• Benign proliferation of fibroblasts and myofibroblasts

Possible risk factors
• Epidural injection
• Tick bite with Borrelia afzelii
• Trauma reported in <15% of cases

Complications
• Cranial variety (nodular fasciitis in the scalp) can cause erosion of the underlying outer table of the skull.
• Ossifying fasciitis

History
• Soft-tissue mass, usually <3 cm
• Pain or tenderness
• Often one to two weeks after trauma (no tumor grows this quickly)
• Rapidly growing, usually solitary, slightly tender, soft-tissue mass (or nodule)
• Trauma history obtained in <15% of patients

Physical
• Palpable nodules or small masses have been reported.
• Lesion usually solitary
• Lesions may reach up to 9 cm in size, but most measure <3 cm.

Making the diagnosis
• Biopsy with histopathologic exam

Rule out
• Malignant tumor
• Benign tumor
• Fibromatosis
• Other types of fasciitis
• Proliferative myositis
• Keloid
• Nodular tenosynovitis

Testing to consider
• MRI or CT for determining extent

Prognosis
• Cured by surgical resection
• Recurrences are uncommon (if recurrence, question original pathologic diagnosis).

Treatment
• Surgical excision is usual treatment.
• No further treatment if diagnosis is by excisional biopsy
• Intralesional corticosteroid injections reported to provide rapid resolution of nodular fasciitis in case report

For references, see www.ebscohost.com/dynamed.com.