title: Radiculopathy due to malignant melanoma in the sacrum with unknown primary site.
abstract: Melanoma is an interesting tumor, showing the appearance of metastasis without any trace of its primary lesion. To report a very rare case of malignant melanoma in the sacrum with unknown primary origin. The authors present a case of a 52-year-old man who was admitted with increasing lower back, left buttock, and left lower extremity pain, and dysuria. Plain radiograph, computed tomography scan, and magnetic resonance imaging revealed a destructive lesion in the sacrum and left ilium, which infiltrated the spinal canal and sacroiliac joint. The tumor cells were immunoreactive for HMB-45. The pathological diagnosis was malignant melanoma. No obvious primary malignant melanoma was detected on the skin surface, on the oral or anal mucosa, or in the fundus oculi. Following radiotherapy and chemotherapy, the severe buttock pain disappeared and the patient was able to walk without impediment. However the patient died nine months after initial diagnosis. Malignant melanoma in the sacrum with an unknown primary site, showing S1 radiculopathy is reported for the first time. The melanoma could have been a metastatic tumor of the sacrum, although the primary site was not detected. The incidence of primary melanoma is increasing faster than any other cancer. Thus treatment of patients with spinal metastasis of melanoma is an important challenge for orthopedic surgeons.
authors: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, chuo-ku, Kobe, 650-0017, Japan.
authors: Kenichiro
authors: K
authors: Kakutani
authors: Minoru
authors: M
authors: Doita
authors: Kotaro
authors: K
authors: Nishida
authors: Hiroshi
authors: H
authors: Miyamoto
authors: Masahiro
authors: M
authors: Kurosaka
mesh_terms: D001416:Back Pain / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D004358:Drug Therapy; D017809:Fatal Outcome; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008545:Melanoma / Q000556:secondary* / Q000628:therapy; D008875:Middle Aged; D009382:Neoplasms, Unknown Primary / Q000473:pathology*; D011128:Polyradiculopathy / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D011843:Radiculopathy / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D011878:Radiotherapy; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging / Q000473:pathology; D012447:Sacrum / Q000000981:diagnostic imaging / Q000473:pathology*; D013115:Spinal Canal / Q000000981:diagnostic imaging / Q000473:pathology; D013125:Spinal Neoplasms / Q000556:secondary* / Q000628:therapy; D014057:Tomography, X-Ray Computed; D017211:Treatment Failure; D014555:Urination Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology