Inverted papilloma Nose
Dr. T. Balasubramanian M.S. D.L.O.
Synonyms: Schneiderian papilloma, Benign papilloma of nasal cavity, Inverted papilloma.
Definition: The mucosal lining of nose and para nasal
sinuses is known as Schneiderian membrane, in memory of Victor
Conrod Schnider who described its histology. Papillomas
arising from this membrane is very unique in that they are found
to be growing inwardly and hence the term inverted papilloma.
These papillomas are unique in their history, biology and location.
Papillomas involving the vestibule is not included under this group
because histologically, biologically and behaviour wise it is different.
The lining mucosa of nose and paranasal sinuses is unique
embryologically in the sense that it is derived from the ectoderm, in
contrast to the lining epithelium of laryngobronchial tree which is
derived from endoderm.
Inverted papillomas behave like neoplasms, arising from reserve /
replacement cells located at the basement membrane of the mucosa.
The stimulus for this proliferation is unknown. The resulting
thickening of the epithelium assumes an inverting, fungiform
or combination growth pattern. Depending on the degree of
metaplasia varying amounts of respiratory / cylinderical cells may be
seen in schneiderian papilloma. Rarely the papilloma may be
composed entirely of cylinderical cells, and hence the term
cylinderical cell papilloma is used to describe this subtype.
Anatomic classification of Schneiderian papilloma: Inverted
papilloma can be classified according to its site of occurance i.e.
lateral wall and septal papillomas. They show
differences in their behavior patterns. The septal papillomas
remain confined to the nasal septum and may very rarely involve
the roof and floor of the nasal cavity. Carcinomatous
transformation is rare in septal papillomas.
Papilloma of lateral wall is known to involve multiple sites i.e.
floor, roof of nasal cavity, para nasal sinuses and naso lacrimal
duct. Carcinomatous transformation is common in this
Clinical classification of inverted papilloma was
proposed by Krouse. He used his classification and staging
protocol to decide on the optimal treatment modality of these patients.
T1 - The disease is limited to the nasal cavity alone
T2 - Disease is limited to ethmoid sinuses and medial and superior portions of maxillary sinuses
T3 - Disease involves the lateral or inferior aspects of maxillary sinus or extension into frontal or sphenoid sinuses
T4 - This stage involves tumor spread outside the confines of nose and sinuses. This stage also includes malignancy
Incidence: Inverted papillomas are fairly common
occurring in 1 - 50 of patients with nasal polypi. If all nasal
polypi removed surgically are tested histopathologically then the
incidence could be still more higher. Men are affected more
commonly than women. The age of affliction may range from between
second to seventh decade of life. The mean age of presentation
Etiology: Human papilloma
virus has been implicated as a causative factor in these
patients. This infection in association with mutation of genes
may cause papillomas. Coinfection with Herpes simplex virus may
interact with Human papilloma virus to cause inverted papilloma.
Role of imaging in the diagnosis of inverted papilloma:
CT scan is necessary for determining the optimal surgical approach in
managing these patients. It also has the added advantage of
differentiating other mass lesions involving the nasal cavities.
Classically inverted papillomas occupies the middle meatus and lateral
nasal wall with areas of higher density associated with bony
sclerosis. If contrast is used for CT imaging contrast
enhancement is also seen.
MRI: Is very useful when the tumor has extrasinosal
involvment or show malignant transformation. It also helps in the
differentiation of tumor tissue from inflammatory mucosa.
Gross apprearance of inverted papilloma
apprearance: Nasal papillomas show two architectural
patterns: 1. Papillary and exophytic 2. Inverted with inwardly
invaginating epithelial growth into underlying stroma. A
combination of both patterns also can occur. The papillary form
tends to commonly occur in the nasal septum, while the inverted form
often occurs in the lateral wall of the nose and sinuses.
Microscopy: The papillary form also known as fungiform papilloma
shows epithelial proliferation over a thin core of connective
tissue. Inversion of epithelial masses is usually not
present. In the case of inverted papilloma the predominant
growth is directed inwards into the underlying stroma. The stroma
is not breached in these patients. When they undergo
malignant transformation the stroma is found to be breached.
The predominant cell type in these papillomas is epidermoid in
nature. Intercellular bridges can be clearly demonstrated.
Microscopic mucous cysts can also be identified in both these
types. Keratinisation is very minimal. Excessive
keratinisation is very rare, and should prompt the pathologist to other
diagnosis like malignant transformation.
Clinical features: Patients present with unilateral nasal mass,
commonly fleshy in nature. Sometimes it may occur behind a
sentinel nasal polyp. It commonly involves the nasal cavity,
erodes the medial wall of maxilla and may present inside the maxillay
Symptoms: are usually caused by compression of adjacent structures like
orbit, pterygopalatine fossa, base of skull or soft tissues.
1. Unilateral nasal obstruction
2. Nasal bleeding
3. Nasal discharge
4. Proptosis if lamina papyracea is breached
Surgical removal provides cure in most of the cases. Recurrence
is common in 20% of patients. It is commonly removed pervia
naturalis. If the mass is huge then lateral rhinotomy will have
to be resorted to for complete removal.
2. Malignant transformation
Copyright drtbalu 2007