Nasopharyngeal Amyloidosis Extending to Larynx: A Rare Clinical Presentation

INTRODUCTION

Amyloidosis is a pathology characterized by the deposition of extracellular proteinaceous material, resulting in damage to the tissues. Amyloidosis can be classified as primary (70%), and secondary (3%) and further into localized and systemic. Amyloidosis in head and neck region is rare and is most frequently localized, with only few systemic forms.^1–3 A total of 19% of the cases involving the head and neck area mainly affect the oropharynx and the larynx.⁴ The presenting symptoms include nasal obstruction, recurrent epistaxis, posterior rhinorrhea or otologic complaints involving eustachian tube dysfunction.¹ Proteinuria, which is often the first symptom in the systemic type, and other manifestations like peripheral neuropathy, dementia, cognitive dysfunction, and organ dysfunction of the liver, kidney, heart, or spleen were absent, ruling out systemic involvement.¹ Amyloidosis of the nasopharynx is rare, with very few reports in the literature. We report a case of nasopharyngeal amyloidosis extending into the larynx mimicking a tumoral process.

CASE DESCRIPTION

A 49-year-old female presented with a history of progressive voice change for 1 year, worsened in the last 6 months, with no associated nasal or laryngeal symptoms.

On clinical examination, the nasal cavity and the oral cavity were normal.

On further evaluation with flexible video laryngoscopy, showed multiple swellings with a yellowish hue seen in the nasopharynx, oropharynx, and supraglottis extending to the right side of the glottis, right vocal cord appeared bulky with normal mobility. Left cord normal (Fig. 1).

The patient was planned for a biopsy of the swelling under the laryngeal mask airway; a biopsy was taken from the nasopharynx, the mass was firm in consistency, with profuse bleeding.

Histopathology revealed focal respiratory epithelium with the presence of prominent eosinophilic amorphous acellular material with few plasma cells.

The extracellular deposits were congophilic and showed apple–green birefringence under polarized light, confirming the diagnosis (Fig. 2).

Staged excision planned even though the nasopharyngeal lesion was extensive, the laryngeal lesion was considered first to relieve the airway obstruction.

The tissues were immunoassayed with CD138 test; no substantial plasma cells were seen.

Considering, the histopathological diagnosis patient underwent a tracheostomy to secure the airway followed by staged microlaryngoscopic debulking of the swellings done with coblator after taking an incision over the lesion in the right false vocal cord pushing the true vocal cord inferiorly to preserve the voice.

The patient was decannulated after 48 hours after confirming adequate airway with flexible video laryngoscopy.

She was referred to a medical oncologist for further evaluation to rule out Systemic amyloidosis. She was advised for a two-dimensional echocardiogram (2D echo), and renal, and liver function tests showed normal values. She was also evaluated with Serum free light chain (kappa and lambda) assay and showed elevated kappa free chain—39.2 (6.7–22.4 mg/L) levels, indicating primary amyloidosis [amyloid light-chain (AL) type] and serum protein electrophoresis, in this myeloma band was not detected and total protein was normal—7.2 (6–8 gm/dL). The elevated kappa light chain indicates primary systemic amyloidosis AL type, but since the patient had no systemic complaints and all other biochemical parameters including total proteins were normal, treatment of systemic amyloidosis was not indicated.

The patient was followed up at regular intervals for 1 year with a flexible video laryngoscopy examination, patient was symptomatically better initially, she then presented with difficulty breathing post 1-year follow-up. Flexible video laryngoscopy showed multiple amyloidosis swellings over the true and false vocal cords and in the nasopharynx and underwent coblation-assisted debulking of the swellings until adequate airway was achieved (Fig. 3).

DISCUSSION

Amyloid was first described by Rokitansky in 1842. It was not until 1853 that Virshow termed these lesions “amyloid” in the belief that carbohydrate was the main constituent.⁴ Even though the localized amyloidosis is a rare and slow-growing pathology and considered benign tumors, they may be aggressive locally leading to osteolysis.

The main differential diagnosis is a malignant tumor, hence the importance of histopathological confirmation. The recurrence rate approximates zero, but the rare presentation and slow progression of this condition make the surveillance mandatory.⁴

The onset of amyloidosis is usually in the fourth to eighth decades. It mainly affects males, with a sex ratio of 3–1.5 but the etiology and exact pathogenesis remain unknown.⁴

The localized form usually follows a slow and benign clinical course with a favorable prognosis of 90.6%.³

CONCLUSION

A complete clinical and paraclinical work-up is required for the positive diagnosis of primary or secondary amyloidosis. It is a benign but locally aggressive pathology. Since the disease involves the airway, morbidity is high; so, postsurgical follow-up is essential to look for localized complications and even to rule out systemic involvement.

REFERENCES

1. Salil S, Eugene O, Miroslav R, et al. Amyloidosis in ENT: Review of the literature and a unique rhinology case. Glob J Oto 2018;16(1):555926. DOI: 10.19080/GJO.2018.15.555926.

2. Jacques TA, Giddings, CEB Hawkins PN, et al. Head and neck manifestations of amyloidosis. Otorhinolaryngol 2013;6(1):35–40. Corpus ID: 31070230.

3. Wahid NW, Abed T, Meghji S, et al. Localized sinonasal amyloidosis. Allergy Rhinol (Providence) 2019;10:2152656719860821. DOI: 10.1177/2152656719860821.

4. Durbec M, Ambrun A, Barnoud R, et al. Localized nasopharyngeal amyloidosis. Eur Ann Otorhinolaryngol Head Neck Dis 2012; 129(3):160–162. DOI: 10.1016/j.anorl.2011.10.010.