Inflammatory myofibroblastic tumor of bone: two cases occurring in long bone

Abstract

Inflammatory myofibroblastic tumor (IMT) is an unusual tumor composed of differentiated myofibroblastic spindle cells usually accompanied by numerous plasma cells and lymphocytes. IMT was originally described in the lung; occurrence in a long bone is rare. We present two examples of IMT arising in a long bone: one in the humerus and one in the femur. In both cases, imaging shows a poorly delineated osteolytic lesion with cortical bone destruction that aggressively extends into surrounding soft tissue. Histologically, the lesion is dominated by differentiated spindle cells with aprominent collagenous stroma and an inflammatory component including plasma cells and lymphocytes, and with positive immunoreactivity for anaplastic lymphoma kinase. The absence of cytologic atypia helps differentiate this lesion from malignant spindle cell tumors.

Soft-tissue inflammatory myofibroblastic tumors (IMTs) of the limbs: potential and limits of diagnostic imaging

“…Although IMTs of long bone have recently been described [19], to our knowledge, no radiological data regarding soft-tissue IMTs of limbs have been reported. Therefore, the aim of this retrospective study was to evaluate the potential of diagnostic imaging in the identification, localization, and characterization of softtissue IMTs of limbs with correlation to differential diagnosis and therapy.…”

“…Little attention has been paid to IMTs' localization in limbs and extremities [18,19]. At these sites, the identification of an expansive lesion combined with locally aggressive features creates problems in differential diagnosis with malignant neoplasms, which not only require demolitive surgical approaches but also post-surgical chemo and radiotherapy.…”

Inflammatory myofibroblastic tumor of the thigh without bone involvement: a case report

“…Though reports of postsurgical, posttraumatic, and postinfectious cases have prompted speculation that the process is initially reactive, these patients will fall into an overtly neoplastic disease category [5]. …”

“…IMTs are commonly found in the lung [2-4]. Extrapulmonary IMTs occur in nearly every site in the body, however, it is unusual for IMTs to exist in the lower extremities without bone involvement [1,3-5]. Herein, we illustrate an unusual case of an IMT of the thigh without bone involvement.…”

Intraosseous Inflammatory Myofibroblastic Tumor of the Twelfth Thoracic Vertebra

“…While IMTs seem to localize predominantly in the viscera (e.g., lung) and soft tissue (e.g., mesentery and omentum) 2 , they arise very infrequently in bone. Their occurrence has been reported in cranial bones [10][11][12] , long bones 13,14 , the sacrum 9 , and the iliac bone 15 . IMTs in the spinal system are also reported [16][17][18][19] , but primary occurrence in a vertebral body is extremely rare 1 .…”