Fact-sheet: Inverted papilloma
Updated on 03/12/2018 at 4:55 PM
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Definition
Rare benign sinonasal tumor
Adults aged 50 to 60 years, can occur at any age
Sex ratio: M/F = 3/1
Bilaterality: 4-9%
Multifocality: <5%
Poorly understood etiopathogenesis, HPV viral involvement ++
Clinical features
Nonspecific
Unilateral nasal obstruction
Anosmia
Rhinorrhea
Epistaxis: predictive sign of malignant transformation
CT
Hypodense mass with lobulated surface, heterogeneous enhancement
Calcifications (bone lysis or tumoral calcifications)
Associated bone lesions: remodeling – thinning – lysis
MRI
T1 and T2 hyposignal
Cerebriform appearance, highly suggestive
Lobulated contours
Heterogeneous enhancement, less than mucosal enhancement
Possible associated inflammatory lesions: mucoid impactions with T1 hypersignal; polyp; mucosal hyperplasia
Management
There is no medical treatment.
Wide surgical excision given the risk of malignant transformation.
Classification
KROUSE classification
STAGE 1: disease confined to the nasal cavity
STAGE 2: involvement of the osteomeatal complex, ethmoid sinus, or medial or superior wall of the maxillary sinus, with or without extension into the nasal cavity and without signs of malignancy.
STAGE 3: disease involving the lateral, inferior, anterior, or posterior walls of the maxillary sinus, possibly the sphenoid sinus, frontal sinus, medial wall of the maxillary sinus, ethmoid sinus, and nasal cavity, without signs of malignancy.
STAGE 4: extranasal or extrasinus extension. Tumors with signs of malignancy.
Differential diagnosis
On CT, the same as for maxillary sinusitis, plus:
- Kilian polyp
- aspergilloma
- pyocele