Address for correspondence : Il-Ho Park, MD, PhD, Department of Otorhinolaryngology-Head and Neck Surgery, Korea University College of Medicine, 148 Gurodong-ro, Guro-gu, Seoul 152-703, Korea
Tel : +82-2-2626-3188, Fax : +82-2-868-0475, E-mail : parkil5@korea.ac.kr

Introduction

The inferior turbinate is a finger-like structure located at the lateral nasal wall and is the largest turbinate. It comprises a central osseous core articulating with the maxilla nasal surface, the palatine bone perpendicular plate, and the outer mucosal layer.1) The structure plays an important role as the first gateway to the respiratory system. It regulates inspiratory resistance to ensure an appropriate negative intrathoracic pressure for comfortable inspiration and changes the inspiratory lamellar airstream into turbulent flow. The inferior turbinate is also an essential component of the nasal defense system and contributes to mucociliary transport, innate immunity, and adaptive immune function.2,3) The significant amount of mucosa, submucosa, vascular, and connective tissue within the inferior turbinate underlies this defensive function.
Nasal obstruction is the most common symptom caused by inferior turbinate disease, and nasal obstruction secondary to inferior turbinate hypertrophy is commonly encountered in clinical rhinology. Therefore, practitioners are primarily focused on resolving hypertrophy-induced obstruction. Clinically important histopathologic findings are rarely found in these cases. In a study measuring the frequency and clinical relevance of unanticipated histopathologic results in 714 inferior turbinate specimens, there were no clinically significant unanticipated findings reported.4)
Constant external stimuli affect the function, shape, and surface contour of the inferior turbinate, and as a result, visually distinguishing normal and abnormal tissue is difficult. The morphology can vary according to the characteristic of the inspired air. The rarity of diseases other than hypertrophy and variable morphology often delays the diagnosis fatal disease in the inferior turbinate. Therefore, to determine the factors correlated with delayed diagnosis of histopathologic lesions, the present study reviewed the clinical presentations and diagnoses in patients with lesions originating and limited to the inferior turbinate.

Materials and Method

The medical records of all patients who underwent endoscopic biopsy to confirm histopathologic findings of an inferior turbinate lesion at the Korea University and Hospital from 2002 to 2013 were retrospectively reviewed. Review of the patient medical records was approved by the Institutional Review Board of Korea University and Hospital. The procedure, indication, and pathologic diagnosis were identified based on the surgical and pathologic reports. Patients were excluded from the study if the specimen was submitted for routine pathologic analysis after turbinate surgery and diagnosed as hypertrophic rhinitis, or if concurrent sinus or nasal cavity involvement beyond the inferior turbinate was identified on endoscopy or radiography. The medical record of past medical history, physical examination, radiologic findings, histopathologic results, treatment course, and follow-up examinations were analyzed.

Results

A total 21 patients were included, comprising 11 female and 10 male aged 24 to 86 years, with a mean age of 50 years. In 18 patients, excisional or incisional inferior turbinate biopsies were histologically evaluated; the remaining three patients were diagnosed incidentally after septoplasty or endoscopic sinus surgery. Twelve different conditions were diagnosed based on microscopic analysis (Table 1). Nine cases were diagnosed as benign tumors: 3 vascular leiomyomas, 3 pyogenic granulomas, 1 cavernous hemangioma, 1 pleomorphic adenoma, and 1 Schneiderian papilloma. Seven cases were diagnosed as malignant tumors: 4 natural killer (NK)/T cell lymphoma, 1 ALK-negative anaplastic T-cell lymphoma, and 1 malignant lymphoma.
Nasal obstruction and epistaxis were the most frequent patient complaint. Foul odor and nasal stiffness were also reported (Fig. 1A). The medical records were reviewed to identify the number of clinics that patients visited previously before evaluation at our hospital. Twelve patients visited only one clinic previously, and six patients visited over three different clinics before presenting to our hospital (Fig. 1B). Inferior turbinate mucosal ulceration was the primary endoscopic finding in 9 patients. Other endoscopic findings, in order of frequency, included crusting, mass lesion, and irregular mucosa (Fig. 1C). Seven of 21 patients required additional treatment postoperatively including concurrent chemo-radiation, chemotherapy, radiation therapy, immunosuppressive therapy (steroid or methotrexate), and antituberculosis therapy (Fig. 1D).
The clinical data of patients who visited more than three different clinics before our hospital, thus delaying diagnosis, was assessed (Table 2). The patients were divided into two groups: Group A patients were recommended biopsy for histopathologic diagnosis at the first or second clinical evaluation, and Group B patients visited more than three different clinics before visiting our hospital. In Group A, ulceration and a large mass lesion were the primary findings (Fig. 2). In Group B, small protruding mass and inferior turbinate hypertrophy were observed endoscopically (Fig. 3). Group B patients were diagnosed with malignant melanoma, NK/T cell lymphoma, cavernous hemangioma, vascular leiomyoma (2 cases), and pleomorphic adenoma; the chief complaints were nasal obstruction (4 cases) and frequent epistaxis (2 cases).

Discussion

In the present study, approximately two cases of clinically significant inferior turbinate histopathology were encountered each year over the study period; additional treatment following biopsy was required in over half of the cases. Approximately one-quarter (6/21) of patients visited more than three different hospitals before presenting to our hospital. The most frequent symptom was nasal obstruction with subtle inferior turbinate changes. In total, 9 benign tumors, 7 malignant tumors, 2 infectious lesions, and 3 autoimmune conditions were diagnosed; among the cases with delayed diagnosis, half were malignant tumors including mucosal melanoma and NK/T cell lymphoma.
Structurally, the inferior turbinate is quite variable. The inferior turbinate is characterized by large venous cavernous sinusoids; the sinusoids create a specialized inflatable organ capable of adapting to the functional demands of the nasal airway, particularly to heat and humidify inhaled air. As the sinusoids distend with blood, the inferior turbinate swells and may obstruct the airway lumen.5) Inferior turbinate hypertrophy is the most common cause of symptomatic nasal obstruction6) and occurs in various forms of rhinitis including allergic rhinitis and vasomotor rhinitis. In simple reactive inferior turbinate hypertrophy, the tissue remains highly responsive to sympathetic stimulation, and nasal obstruction can usually be resolved with decongestant medication.7) In contrast, hypertrophy caused by a tumor is poorly responsive to local decongestants because the sinusoid tissue is infiltrated by neoplastic tissue. Presumably, if measurements performed after topical decongestant administration show no significant change, then effort is needed to locate the causative lesion.
The inferior turbinate comprises highly resistant tissue to meet the relentless external environment, but despite this, it is not free from disease. Several clinically important pathologic lesions including cancer, vasculitis, granulomatous disease, and benign neoplasm can occur in the inferior turbinate, but the incidence of inferior turbinate disease has not been reported previously. Only isolated case reports of vascular leiomyoma, pleomorphic adenoma, fibrous dysplasia, angiofibroma, inverted papilloma, and adenosquamous carcinoma presently exist.8,9,10,11,12,13) In the present study, numerous pathologic lesions were found to originate from the inferior turbinate including benign neoplasms (vascular leiomyoma, pyogenic granuloma, cavernous hemangioma, pleomorphic adenoma, and Schneiderian papilloma), malignant neoplasms (NK/T cell lymphoma, anaplastic T-cell lymphoma, undifferentiated carcinoma, and malignant mucosal melanoma), infectious disease (Mycobacterium tuberculosis), and autoimmune disease (Churg-Strauss syndrome and Wegener's granulomatosis).
In a related study, Daniero, et al.4) assessed the diagnostic efficacy of routine microscopic examination of surgically removed inferior turbinate. The pathology reports of 714 inferior turbinate specimens were reviewed, but none had clinically relevant unanticipated histopathologic findings. They concluded that a value-based approach to processing grossly unremarkable turbinate tissue could provide significant cost savings by waiving histologic processing and subsequent microscopic evaluation. Similarly, 581 pathology reports following inferior turbinate surgical biopsy were retrospectively reviewed over 11 years from 2002 to 2013. In the present analysis, three unexpected histopathologic findings were diagnosed histologically. However, although routine histologic examination is ineffective, efforts to detect subtle pathologic indicators of inferior turbinate should continue.
In conclusion, in patients with nasal obstruction nonresponsive to multiple therapeutic attempts, neoplastic lesions that change the basic inferior turbinate morphology should be suspected to avoid delaying diagnosis and proper treatment.

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