Benign Calcifying Pseudotumor of the Craniocervical Junction: Rare Presentation in an Infant

Introduction: Benign calcifying pseudotumor is a rare mass lesion of unknown etiology, which can arise in virtually any anatomic location. We report the first case described in an infant.

Case Report: A 10-month-old girl was evaluated for torticollis not responding to physical therapy. She was otherwise neurologically and developmentally normal. Cervical spine imaging revealed a heterogeneous calcified mass occupying the dorsal craniocervical junction with a large anterior exophytic component. Percutaneous biopsy was nondiagnostic; angiography did not demonstrate hypervascularity or vascular pedicle. The patient was taken to surgery for resection. Posteriorly, a fibrous extradural lesion eroding the atlantoaxial bony elements and occipital condyle was resected. Anteriorly, operative exploration was negative. Subsequent imaging showed no evidence of the previously seen anterior exophytic lesion. There was no postoperative neurologic deficit, and torticollis subjectively improved. Pathologic diagnosis was benign calcifying pseudotumor.

Discussion: Calcifying pseudotumor is one of several names applied to a mass lesion of unknown etiology consisting of fibrosis and monocytes. It is often radiographically indistinguishable from neoplasm. While most commonly found in the lung and orbit, it has been described in essentially any anatomic location including the central nervous system. Although presumed to result from an immunologic response to infection, foreign body, or necrosis, an underlying causative agent is rarely identified. Within the medical literature, alternate nomenclature has included inflammatory pseudotumor, inflammatory myofibrohistiocytic proliferation, fibrous xanthoma, xanthomatous pseudotumor, pseudosarcomatous myofibroblastic proliferation, and solitary mass cell granuloma.

The incidence of calcifying pseudotumor does not display age, sex, or geographic predilection. There may be an association with cocaine use or Epstein–Barr virus infection. A case report from 2000 described the first diagnosis of spinal intraosseous inflammatory pseudotumor, within the body of C2 in a 60-year-old woman.¹ A case series of 15 patients, none of whom had a lesion involving the central nervous system or spinal column, included four patients younger than 17 years at diagnosis.² A 2012 review identified 56 patients diagnosed with calcifying pseudotumor of the brain (37 cases), spine (15 cases), or craniovertebral junction (4 cases).³ The youngest patient was 4 years' old.

The primary treatment modality is surgical resection. Steroids and immunosuppressive drugs have also been shown to decrease lesion volume; radiation therapy has been rarely employed although its efficacy is uncertain. Malignant behavior is extremely rare.

Conclusion: Inflammatory pseudotumor is a generally benign lesion which causes symptoms primarily from direct mass effect. Although complete excision is curative, prognosis is favorable even with subtotal resection.

References

References

1 Chang H, Park JB, Kim KW. Intraosseous calcifying pseudotumor of the axis: a case report. Spine 2000;25(8):1036–1039

2 Nascimento AF, Ruiz R, Hornick JL, Fletcher CDM. Calcifying fibrous 'pseudotumor': clinicopathologic study of 15 cases and analysis of its relationship to inflammatory myofibroblastic tumor. Int J Surg Pathol 2002;10(3):189–196

3 Nonaka Y, Aliabadi HR, Friedman AH, Odere FG, Fukushima T. Calcifying pseudoneoplasms of the skull base presenting with cranial neuropathies: case report and literature review. J Neurol Surg Rep 2012;73(1):41–47