29th Mar 2021

ICRI CASE OF THE WEEK

Contributed By : Dr. Radhika Daga, Resident
Dr. Jyoti Kumar, Professor

Department of Radio-diagnosis
Maulana Azad Medical College, New Delhi

Copyright of the Case belongs to : Dr Jyoti Kumar

Clinical Details

A 61 year old man presented to OPD with complains of nasal fullness
since 1 year with frequent episodes of headache.

Patient was referred for NCCT evaluation.



• What are the findings?

• What is the differential diagnosis?
• What is the preferred next investigation?



DIFFERENTIALS?

Benign solid soft tissue mass
a. Inverted papilloma most likely in view of hyperostotic bone

Others masses in same location-

a. Olfactory neuroblastoma
b. Antrochoanal polyp

NEXT INVESTIGATION?

Contrast enhanced MRI as it gives better soft tissue characterization
and can differentiate the mass from trapped secretions.



• What are the findings?

• What is the final diagnosis?



Diagnosis

• Inverted Papilloma

• Unilateral polypoidal mass epicentered in left nasal cavity with
bone remodelling and focal hyperostosis seen on CT and diffuse
convoluted cerebriform pattern of enhancement on MRI

Discussion

• Inverted Papilloma (IP) is the most common benign epithelial tumor of the
sinonasal region.

• Frequently seen in 5-6th decades of life with a slight male predominance.
• The name comes from the ‘inverted’ growth pattern of mucosa into the

underlying stroma with intact basement membrane.
• Characteristic location is in the lateral nasal cavity in the region of middle

turbinate or medial wall of maxillary sinus.
• Bilateral and multifocal forms of inverted papilloma are reported but are rare.

CT Findings

• Focal hyperostosis is a localized area of bony thickening which can be either
plaque like or cone shaped and is a hallmark for inverted papilloma.

• Identification is important

• Represents the site of origin of the tumor and needs to be removed during
surgery- inadequate removal is the major contributor to recurrence of the
tumor.

MRI Findings

• A convoluted cerebriform pattern (CCP) seen as alternatively low and high
intensity bands on both T2 weighted and post contrast T1weighted images.

• Has a positive predictive value of more than 80-90%.

• Can rarely be seen in other malignant lesions- esthesioneuroblastoma,
adenoid cystic carcinoma and PNET

• Focal loss of CCP might give clue to squamous cell transformation.

DIFFERENTIALS

a. Olfactory Neuroblastoma
b. Antrochoanal Polyp
c. Malignant lesion

OLFACTORY NEUROBLASTOMA

Points in favour
• Age (bimodal 2nd and 6th decade)
• Epicentered in the nasal cavity

Points against
• Presence of Focal hyperostosis
• Presence of Convoluted cerebriform pattern
• No intracranial extension for the size of the mass

ANTROCHOANAL POLYP

Points in favour
• Expansion with remodeling of bone in characteristic location

Points against
• Age (3-4th decade)
• Sinus reduced in size and not expanded
• Solid enhancement of the mass
• Presence of Focal hyperostosis
• Presence of Convoluted cerebriform pattern

MALIGNANT TUMOR

Points in favour
• Age (>50 years)

Points against
• Well marginated poylpoidal mass
• Expansile remodeling of the bone rather than destruction.
• No extrasinus (orbit/intracranial) or perineural extension seen
• Presence of focal hyperostosis
• Diffuse convoluted cerebriform pattern seen

Teaching Points

Inverted papilloma (IP) is the most common benign epithelial tumor of the
sinonasal region.

Preoperative imaging is not only essential for assessment of the extent of tumor
but also for detection of focal hyperostosis.

Inadequate removal of focal hyperostosis-major contributor to recurrence.

Convoluted cerebriform pattern is a reliable imaging feature on MRI. Diagnostic
in 80% cases.

Intralesional calcific foci/bone destruction and solid contrast enhancement can
differentiate IP from antrochoanal polyp which is a close differential on NCCT.