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1Department of Otorhinolaryngology, University College of Medical Sciences and GTB Hospital, India
2Department of Pathology, University College of Medical Sciences and GTB Hospital, India
Submission:April 22, 2021; Published: May 14, 2021
*Corresponding author:Sarthak Sachdeva and Manisha Yadav, Junior resident, Department of Otorhinolaryngology, University College of Medical Sciences and GTB Hospital, Delhi, India
How to cite this article: Sarthak Sachdeva, Manisha Yadav, Vinod Kumar Arora, Richa Gupta, Vipin Arora, Akanksha Agarwal. A Rare Case of
Recurring Ossifying Fibroma of the External Auditory Canal. Glob J Oto, 2021; 24 (3): 556138. DOI: 10.19080/GJO.2021.24.556138
Fibro-osseous lesions are a group of disorders that can arise from any part of the facial skeleton and include ossifying fibroma, fibrous dysplasia, giant cell lesions etc. Almost 70 percent of these lesions arise in the head and neck. The most common sites affected are maxilla and mandible. Occasionally, they have also been reported in orbitofrontal bone, paranasal sinuses, nasopharynx, and skull base. We report a rare case of recurring ossifying fibroma of the external auditory canal.
Ossifying lesions in the External auditory canal (EAC) are most commonly Exostosis and Osteoma. Exostoses comprise the most common neoplasms of the EAC and are mainly caused by local irritation in the ear . Although exostosis is most common ossifying lesion of EAC, but its overall incidence is merely 0.6%. Osteomas, which are rarer than exostosis, are usually single, unilateral, squamous bone lesion located laterally with respect to isthmus . Apart from these, exceedingly rarely ossifying fibromas and monostotic fibrous dysplasia have also been reported and are collectively termed as Benign fibro-osseous lesions of the EAC . Here, we describe a rare case of ossifying
fibroma of the EAC which has some histopathological and clinical features differentiating it from the earlier reported cases, and difficulty encountered while managing it because of the high incidence of recurrence after primary excision.
A 50-year-old male presented with occasional otalgia and persistent hearing impairment for six months. Patient had a history of head trauma 1.5 years back. Otoscopy revealed an extensive skin covered firm mass completely filling his left EAC. Pure tone audiogram (PTA) showed a 60 dB hearing loss and an air–bone gap of 40dB in the left ear (Figure 1a).
High-resolution CECT of the temporal bone showed a minimally
enhancing soft-tissue density lesion in the EAC measuring
1.7x0.7x0.3cm (tr*cc*ap) with central osteoid differentiation
measuring 8mm. This pedunculated lesion was seen arising from
the antero-inferior wall of the lateral most point of the bony EAC
medially reaching up to the tympanic membrane and laterally up
to the external orifice of the bony external auditory canal. A small
lytic defect was also noted in the anterior bony auditory canal. No
e/o periosteal reaction was seen. The ossicle chains were intact,
and the middle ear cavity was free (Figure 1b).
An excisional biopsy of the mass was carried out under local
anesthesia, leaving the skin under the mass and the eardrum
intact. Histopathological examination revealed osteoma like bone
formation with islands of bony trabeculae and sparse osteoblastic
areas in a cellular fibrous stroma (Figure 2a). Minimal ‘osteoblastic
rimming’ was also seen at the advancing front of the bony islands
in surrounding soft tissues and dermis (Figure 2b). Subsequently,
there was an improvement in hearing loss postoperatively, but the
hearing loss recurred over the next few months. An endoscopic
examination of the EAC showed recurrence of similar mass which
was further confirmed by radiological examination suggesting the
need of a more robust procedure with complete removal and large
canaloplasty for this patient.
Fibro-osseous lesions form a diverse group of conditions with
similar histology but varying etiologies. They are lesions with misshaped
trabeculae of compact bone embedded in the surrounding
connective tissue. They seem to abruptly arise over the healthy
bone . Benign fibro-osseous lesions include non-neoplastic
lesions such as fibrous dysplasia and neoplastic lesions such as
ossifying fibroma, giant cell tumor, osteoma, osteoblastoma, and
aneurysmal bone cysts . These lesions need to be differentiated
so that the aggressiveness of the lesion can be anticipated, and the
surgeon can choose from a plethora of treatment options ranging
from simple enucleation to complete excision.
Biopsy done from our case shows islands of bony trabeculae in
a fibrous stroma with infiltration into surrounding soft tissue and
dermis with minimal activity and occasional ‘osteoblastic rimming’
over the margins of advancing bony trabeculae (Figure 2a & 2b).
These findings are consistent with benign fibro-osseous lesions,
possibly, ossifying fibroma. Pertaining to the rarity of ossifying
fibroma, it may be misdiagnosed as a more common condition
like osteoma. This is because they share similar histopathological
features with very minute differentiating characters and their
diagnosis requires clinical and radiological correlation as well as
good knowledge of subtle histological differences (Table 1).
Ossifying fibroma is a benign fibro-osseus lesion that consists
of conventional ossifying fibroma and juvenile ossifying fibroma.
Conventional ossifying fibroma could be ossifying, cementifying
or storiform form. Juvenile ossifying fibromas are aggressive
and further divided into trabecular and psammomata varieties
[5,6]. Our histopathological findings show greater similarity to
conventional ossifying fibroma which in literature has been known
to show irregular lamellar bony trabeculae with hypercellular
fibrous stroma. There is no atypia of fibroblastic cells and there
is no mitosis. Mature lesions show minimal osteoblastic rimming
Similar cases that have been reported in the past are
summarized in Table 2. The current case is unique as it was
observed that the pedunculated mass occupied the bony
part of the EAC only rather than cartilaginous EAC which is
reported by Ramirez et al.  in his series of 5 cases. Our case
histopathology also showed characteristic ‘osteoblastic rimming’
which has not been described in previous studies. Although
benign but if left untreated they may locally destruct the bony
EAC, temporomandibular joints, middle ear, mastoid cavity etc.
and manifest in the form of various symptoms associated with
it . Malignant transformation is not reported in the literature.
The various treatment modalities available for such lesions
are enucleation, curettage, and resection with reconstruction.
Recurrence rates of up to 28% have been reported in literature
. Recurrent cases of ossifying fibroma have been found to
be larger in size and with an extensively altered radiographic
appearance as it is believed that surgery can reactivate the
growth of lesion . Hence the preferred modality of treatment
in such lesions should be complete excision, canaloplasty and
This is a rare case report of recurring ossifying fibroma of
EAC which probably developed from a progressive inflammatory
reaction with fibrosis, osseous metaplasia, and eventual
calcification. Such patients require a complete removal of all
tissue along with a large canaloplasty and reconstruction to
correct the conductive hearing loss. Also, a long-term follow-up of
these patients is essential as recurrences can occur up to 10 years