Inflammatory myofibroblastic tumor of the thigh: presentation of a rare case and review of the literature

PET/CT Imaging of Inflammatory Myofibroblastic Tumor of the Thigh

A 13-year-old male patient presented with right leg pain and walking difficulty. Contrast-enhanced magnetic resonance imaging showed a softtissue lesion between muscle groups in the anterior half of the right thigh. The excisional biopsy result ended in an inflammatory myofibroblastic tumor (IMT). The 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan showed hypermetabolism in the multifocal soft tissue lesion and also confirmed that no other distant foci were present. A three-phase Tc-99m-methylene diphosphonate study of the region showed heterogeneously increased vascularity within the region. We described an unusual case of IMT in a pediatric patient and the importance of PET/CT scanning to delineate the lesion.

Anaplastic lymphoma receptor tyrosine kinase-negative inflammatory myofibroblastic tumor of triceps brachii: Case report

Inflammatory myofibroblastic tumor (IMT) is a non-neoplastic benign lesion comprising various inflammatory cells, including myofibroblasts and vascular tissues. It is a rare tumor that sometimes shows similar signs and progression as malignant tumors. The anatomical sites of IMTs include the lungs, liver, orbit, skin, mesentery, and maxillary sinus, but they rarely occur in the limb musculoskeletal system. To our knowledge, no case of neurological symptoms caused by the tumor in the triceps brachii muscle has been reported. In this article, we report the case of a 42-year-old male patient with an IMT that grew rapidly in the triceps brachii muscle and consequently caused symptoms of ulnar nerve lesion owing to its increasing size. The patient showed no ulnar nerve lesion symptoms after undergoing wide excision and was diagnosed with anaplastic lymphoma receptor tyrosine kinase- negative IMT.

Inflammatory myofibroblastic tumor of the lumbar spinal canal: A Case Report With Literature Review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is a rare type of mesenchymal tumor. IMT can arise in multiple anatomic locations. IMT of the lumbar spinal canal is exceptionally rare.

PATIENT CONCERNS

Here, we report the case of a 56-year-old male patient with an IMT who was in good health until 1 year prior to admission, when he began experiencing pain in both lower extremities and the lower back.

INTERVENTIONS

A space-occupying lesion in the lumbar canal was identified by magnetic resonance imaging and then surgically resected.

DIAGNOSES

Histopathological analysis of the lesion revealed a composition of mucous edema, inflammatory cells, collagenous fibers, and spindle cells that were diffuse and positive for smooth muscle actin and CD68; focal positive for vimentin and desmin; and negative for CD34 (marker of vascular endothelial cells), CD21, CD23, CD35, S-100, Epstein-Barr virus infection, Ki-67, and anaplastic lymphoma kinase. Thus, the diagnosis was an IMT of the lumbar canal.

OUTCOMES

In the spinal canal, IMT should be considered in the evaluation of tumors although it is a very rare diagnosis. It is a benign lesion, but it has potential for invasion and recurrence.

LESSONS

There are no characteristic imaging features of these tumors, but they can be addressed by complete surgical excision. Patients with these lesions should undergo frequent long-term follow-up to detect and address recurrence.

Clinicopathological Study of 18 Cases of Inflammatory Myofibroblastic Tumors with Reference to ALK-1 Expression: 5-Year Experience in a Tertiary Care Center

Background

Inflammatory myofibroblastic tumor is a histopathologically distinctive neoplasm of children and young adults. According to World Health Organization (WHO) classification, inflammatory myofibroblastic tumor is an intermediate-grade tumor, with potential for recurrence and rare metastasis. There are no definite histopathologic, molecular, or cytogenetic features to predict malignant transformation, recurrence, or metastasis.

Methods

A 5-year retrospective study of histopathologically diagnosed inflammatory myofibroblastic tumors of various anatomic sites was conducted to correlate anaplastic lymphoma kinase-1 (ALK-1) expression with histological atypia, multicentric origin of tumor, recurrence, and metastasis. Clinical details of all the cases were noted from the clinical work station. Immunohistochemical stains for ALK-1 and other antibodies were performed. Statistical analysis was done using Fisher exact test.

Results

A total of 18 cases of inflammatory myofibroblastic tumors were found during the study period, of which 14 were classical. The female-male ratio was 1:1 and the mean age was 23.8 years. Histologically atypical (four cases) and multifocal tumors (three cases, multicentric in origin) were noted. Recurrence was noted in 30% of ALK-1 positive and 37.5% of ALK-1 negative cases, whereas metastasis to the lung, liver, and pelvic bone was noted in the ALK-1 positive group only.

Conclusions

Overall, ALK-1 protein was expressed in 55.6% of inflammatory myofibroblastic tumors. There was no statistically significant correlation between ALK-1 expression, tumor type, recurrence and metastasis. However, ALK-1 immunohistochemistry is a useful diagnostic aid in the appropriate clinical and histomorphologic context.