title: Primary anaplastic large cell lymphoma of the psoas muscle: a case report and literature review.
abstract: Primary anaplastic large cell lymphoma (ALCL) of skeletal muscle is very rare. We report a case of ALCL arising from the left psoas muscle. A 14-year-old girl presented with a large left inguinal tumor. She complained of a 2-month history of left leg pain, which had been exacerbated upon leg extension, and she had become aware of a rapidly growing left inguinal tumor 3 weeks before admission. CT scan and MRI revealed a large tumor arising from the left major psoas muscle and protruding into the inguinal region. In view of the tumor's location and the patient's age, soft tissue tumors such as rhabdomyosarcoma and primitive neuroectodermal tumor were initially considered. However, histopathological examination yielded a diagnosis of anaplastic lymphoma kinase-positive ALCL. The serum level of soluble interleukin-2 receptor was markedly elevated at 50,414 U/ml, and this also strongly suggested ALCL. Although rarely reported, ALCL is an important entity to consider in the differential diagnosis of skeletal muscle tumors in children and young adults.
authors.affiliation: Department of Pediatrics, Wakayama Medical University, Wakayama City, Japan. nami@wakayama-med.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Kounami
authors.forename: Keiko
authors.initials: K
authors.lastname: Shibuta
authors.forename: Megumi
authors.initials: M
authors.lastname: Yoshiyama
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Mitani
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Katsunari
authors.initials: K
authors.lastname: Takifuji
authors.forename: Norishige
authors.initials: N
authors.lastname: Yoshikawa
mesh_terms: D000293:Adolescent; D002889:Chromosomes, Human, Pair 2; D002895:Chromosomes, Human, Pair 5; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017728:Lymphoma, Large-Cell, Anaplastic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D019042:Muscle Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D016658:Psoas Muscles / Q000473:pathology*; D011877:Radionuclide Imaging; D014057:Tomography, X-Ray Computed; D014178:Translocation, Genetic