Treatment and Prognosis of Inflammatory Pseudotumor of the Skull Base

Background: Inflammatory pseudotumor (IPT) of the skull base is a rare, locally destructive lesion that is often treated with resection, steroids, antibiotics, radiation, biologics, or a combination thereof. We define the current population of skull base IPT patients, explore the impact of treatment on outcome, and assess the prognosis of the disease.

Methods: We performed a single-center retrospective study of adults with IPT of the skull base. Patient history, serologies, imaging studies, and treatment course were obtained from chart review. The primary outcome was radiographic progression after treatment. Outcomes and tumor location was examined. Radiographic progression was fit to a logistic model using sex, age, anatomic involvement, comorbid autoimmune disease, immunodeficiency, obesity, ethanol use, smoking history, and elevated erythrocyte sedimentation rate (ESR) as predictor variables.

Results: The demographics of 21 patients with IPT are reported in Table 1. Corticosteroids were the most widely used treatment (80.1%). Disease-modifying antirheumatic drugs (DMARDs) (33.3%), resection (28.6%), radiation (23.8%), antibiotics (14.3%), rituximab (9.5%), and antivirals (4.8%) were also used. At 50.7 months, 50.8% had evidence of radiographic progression. At 10 years, antibiotic, antiviral, and radiation trended superior to DMARD, steroid, or surgical therapy (p = 0.93). Patients receiving local therapy trended toward having a better response than systemic therapy (p = 0.60; [Fig. 1]). On average, IPT of the orbit tended to require 2.4 treatment modalities, compared with 2.0 for pharyngeal IPT, and 1.3 for posterior masses (p = 0.14). Seventy-five percent of orbital IPT underwent radiographic progression, compared with 71% of pharyngeal IPT and 50% of posterior masses (p = 0.62) ([Fig. 2]). Sixteen patients were used to create the logistic model of radiographic progression. The Cox-Snell R-square was 0.71 (p = 0.03). No individual variables were statistically significant.

Conclusion: To our knowledge, this is among the largest sample of cases describing the presentation, treatment, and prognosis of IPT of the skull base. Our data suggest there may be an improved response with local therapy over systemic therapy and better prognosis among posterolateral masses.

Table 1 Summary of presentation

Characteristic		Totals
Demographics		n = 21
	Age in years, mean (range)	51.8 (24–85)
	Sex, male/female	7/14
	BMI in kg/m2, mean (range)[a]	31.9 (20.7–45.7)
History, no.		n = 21
	Daily EtOH use at presentation	1
	History of tobacco use	12
	Immunosuppression	6
	Autoimmune disease	6
Anatomic location, no.		n = 21
	Orbit	8
	Pharyngeal	7
	Lateral or posterior	6
Serologies, no.		n = 16
	Elevated ESR	9

^a BMI available for 19 patients.

Fig. 1 Treatment and inflammatory pseudotumor progression.

Fig. 2 Location of inflammatory pseudotumor and general prognosis.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
12 February 2021