Saturday, March 21, 2015

Neurofibromatosis type 1 presenting as a large growth on the buttock

A huge unsightly tumor growing on the back and buttock would be embarrassing for anyone, but doubly so for a teenager. I really feel sorry for the young man described in today's blog post - the victim of a fairly common genetic condition.

Neurofibromatosis type 1, also known as von Recklinghausen's disease, is an autosomal dominant disorder characterized by changes in skin pigmentation and the growth of tumors along nerves in the skin, brain, and other parts of the body. It affects approximately 1 in 3,000 individuals. Neurofibromatosis type 1 is caused by a mutation in the NF1 gene, located on chromosome 17q. The product of this gene - a protein called neurofibromin - acts as a tumor suppressor, which means that it keeps cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the NF1 gene lead to the production of a nonfunctional version of neurofibromin that cannot regulate cell growth and division.

The signs and symptoms of this condition vary widely among affected people. Since early childhood, almost all people with neurofibromatosis type 1 have multiple café-au-lait spots, which are flat darkened patches on the skin. These spots increase in size and number as the individual grows older. Most adults with neurofibromatosis type 1 develop neurofibromas - benign tumors that are usually located on or just under the skin. These tumors may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Some people with neurofibromatosis type 1 develop cancerous tumors that grow along nerves, known as malignant peripheral nerve sheath tumors. People with this condition also have an increased risk of developing other cancers, including brain tumors and leukemia.

Neurofibromas, while benign, can grow to a large size and significantly impair a patient's quality of life, as the following case shows. A 19-year-old Pacific Islander suffered from a large growth involving the back and buttock. The mass, present since birth, had been growing slowly over the past several years. Not surprisingly, the resulting disfigurement was a source of substantial embarrassment for the patient.

 A case of neurofibromatosis type 1: a large growth involving the lower back and buttock.

Physical examination revealed a soft tissue mass of the back that extended from the tenth thoracic vertebra to the inferior gluteal clefts. The growth was hyperpigmented and corrugated. No additional neurofibromas or café-au-lait spots were noted. Neurological examination was normal. CT scan images demonstrated the mass to be confined to the subcutaneous tissues, without extension into the underlying musculature.

The patient underwent a radical resection of the mass down to the paravertebral fascia. The wound was initially managed with negative pressure wound therapy, and once a bed of healthy granulation tissue was created, autogenous skin was harvested from the upper back and grafted to the granulation bed. Two weeks later, excellent graft take was noted and the patient returned home.

The final result after surgery. Images from: Washington et al. (2010)


Washington EN, Placket TP, Gagliano RA, Kavolius J, Person DA. (2010) Diffuse Plexiform Neurofibroma of the Back: Report of a Case. Hawaii Med J. 69(8): 191–193.

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