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

Abstract

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.

Figure 1

Plain and enhanced MRI revealed a space-occupying lesion at the L4/5 level located in the epidural space of the spinal cord. (A–C) Magnetic resonance imaging (MRI) scans (A: T1WI SAG; B: T2WI SAG; C: T2WI-FS SAG) showing a nonhomogeneous soft tissue mass arising from the lumbar spinal canal. MRI enhanced scans (D: T1WI SAG) showing a mass in the lumbar spinal canal with inhomogeneous enhancement. The modified area was showing with white arrows inserted on the picture. MRI = magnetic resonance imaging.

Figure 2

Histological examination showed an area of mucous edema, spindle cells showing no nuclear division and no necrosis, and inflammatory cells in dense areas, with obvious degeneration of the collagen fibers. (A) Hematoxylin and eosin staining (original magnification × 200). (B) Hematoxylin and eosin staining (original magnification × 400).

Figure 3

The tumor cells stained diffusely positive for (A) SMA, (B) CD68 (original magnification, × 200), and focal expression of (C) vimentin and (D) desmin (original magnification, × 400), and (E) negative for CD34 (marker of vascular endothelial cells, original magnification, × 200), suggestive of an inflammatory myofibroblastic tumor. SMA = smooth muscle actin.