Desmoid-type fibromatoses involving the brachial plexus: treatment options and assessment of c-KIT mutational status.
OBJECTIVE
Desmoid-type fibromatoses are a locally invasive soft-tissue lesion that is most commonly encountered in abdominal sites. The tumor also affects head and neck areas, particularly the supraclavicular region, where it may encase and distort the brachial plexus and compromise neurovascular structures. Neurosurgeons may be called on to treat desmoid-type fibromatoses in these sites. The authors describe their experience in treating four patients with desmoid-type fibromatoses involving the brachial plexus and report the results of immunohistochemical analysis of the tumors.


METHODS
Gross-total excision with nerve sparing was the first-line therapy of choice, although the surgery was challenging. Intraoperative identification of the site of tumor origin from musculoaponeurotic tissues by the neurosurgeon was necessary in two of the four cases to achieve a correct frozen section or final pathological diagnosis. Immunostaining for c-KIT (CD117) was undertaken in all cases in light of a previous report of positive CD117 immunoreactivity in abdominal desmoid-type fibromatoses. All four tumors manifested weak focal immunostaining for c-KIT. One of the patients was given adjuvant imatinib mesylate therapy, with limited success. Subsequent polymerase chain reaction testing revealed that three of the four tumors manifested a single base pair change in exon 10 of the c-KIT gene (A to C in two cases and A to G in one case). There was local recurrence in three patients, despite gross-total excision. With the combination of surgery and radiation therapy, local disease control was achieved in three of the four patients.


CONCLUSIONS
This represents the first report of c-KIT sequencing in desmoid-type fibromatoses and suggests a possible biological basis for continuing to explore the use of adjuvant imatinib mesylate therapy.
Seinfeld
Joshua
J
Department of Neurosurgery, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
Kleinschmidt-Demasters
Bette K
BK
Tayal
Shalini
S
Lillehei
Kevin O
KO
D000328:Adult; D020137:Base Pair Mismatch / Q000235:genetics; D001549:Benzamides; D001917:Brachial Plexus / Q000473:pathology / Q000601:surgery; D020516:Brachial Plexus Neuropathies / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005260:Female; D018222:Desmoid Tumors / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics / Q000601:surgery*; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000235:genetics / Q000601:surgery; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics / Q000601:surgery*; D010879:Piperazines / Q000627:therapeutic use; D016133:Polymerase Chain Reaction; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011743:Pyrimidines / Q000627:therapeutic use; D012086:Reoperation
D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit