# Solitary Amyloid Tumor of the Tongue Base

Authors: S. Akyildiz; B. Doganavsargil; S. Göde; A. Veral
Journal: International Journal of Otolaryngology
 (2009)

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## Abstract

The purpose of this article is to present a rare case of localized, solitary amyloid tumor of tongue base and emphasize some of the characteristic features of challenging clinical and histopathologic diagnosis. In this paper, we focused on the clinical and pathological specifications of this rare tumor, so any unnecessary examinations or measures may be spared. Negative staining of amyloid material with AAC and osseous metaplasia noted in the histopathologic examination may not be thought as definite criteria for localized amyloidosis, but a supporter of localized, solitary amyloid tumor diagnosis.


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## Body

## 1. Introduction

Amyloid can affect any site in the
head and neck including the orbit, sinuses, oral cavity, salivary glands,
pharynx, and larynx. Amyloid involvement of tongue is almost always secondary
to systemic amyloidosis and localized involvement is extremely rare [1, 2].The etiology, treatment, and
outcome of systemic amyloidosis are totally different from localized
amyloidosis. The mean survival of patients with systemic amyloidosis is between
5 to 15 months, whereas patients with localized amyloidosis have excellent
prognosis [1].To rule out a systemic amyloidosis
for these patients is extremely critical because this can markedly change the
expected morbidity and mortality [1]. Abdominal fat aspirate is a risk-free
procedure and is the most specific test available as it is positive in 70–80% of patients
with amyloidosis; however, the sensitivity is low and is very technique
sensitive [2, 3].The purpose of this article is to
present a rare case of localized, solitary amyloid tumor of tongue base and
emphasize some of the characteristic features of challenging histopathologic
diagnosis.


## 2. Case Report

A 61-year-old male patient
presented with pyrosis of tongue and a nodular mass in tongue base. Head and
neck examination revealed a1×1 cm well-circumscribed, rubbery, nodular mass
at the right side of the tongue base. His review of systems was negative for
symptoms including fever and weight loss.A computed tomography was performed
and a possible granulomatous or inflammatory mass with calcification was
reported (Figure1). An incisional biopsy was performed
from the mass preoperatively. Histologic examination revealed a benign lesion
without forming a significant mass. The lesion appeared to be under normal
mucosa, within hyalinized muscular and connective tissue which includes focal
chondroid differentiation areas. Transcervical
total excision of the lesion was planned.Figure 1
CT scan of the lesion. The lesion can be seen on the right
side of tongue base.Rough and irregular mass, 2 cm in diameter, was dissected from surrounding normal tissue with
minimal tissue loss and en
bloc excision could be achieved via transcervical suprahyoid approach
(Figure2).Figure 2
En bloc excision of well-circumscribed mass in the tongue
base. M: mentum.Postoperative microscopic examination of the specimen
revealed a well-circumscribed submucosal lesion characterized with
structureless eosinophilic material deposition. Overlying mucosa was inflamed and focally eroded. The amorphous, more or
less homogenous eosinophilic material
resembled amyloid histologically and on Congo red staining, exhibited the classical apple-green
birefringence under polarized
light. Deposits of amyloid were also found in and around the walls of small
blood vessels. Immunohistochemical examination of the matrix with monoclonal
antibody AA-Congo (AAC)
(Dako, Denmark 1/100 dilution) revealed a non-AA-type amyloid deposition (Figure3). At the
periphery of the lesion, there was a prominent chronic inflammatory reaction
rich in mixed kappa and lambda immunoreactive (Neomarkers, Barcelona,
Spain 1/3000, 1/100 dilutions) plasma cells. A giant cell
response to amyloid material was also present. Interestingly, there was a
metaplastic bone tissue surrounding the mass. Focal chondroid differentiation
was also observed either neighboring
the osseous tissue or spread as single chondrocytes in the amyloid matrix
(Figure 4). Thus, the lesion was reported as localized amyloid tumor of tongue
base with focal osseous and chondroid metaplasia.(a) Closer view of
amorphous, fibrillary matrix deposition (hematoxylin and eosin, ×20). (b) Peach-red staining of the material in Congo-red
staining (Congo-red, ×20). (c) Apple-green
birefringence under polarized light (Congo-red, polarization microscope, ×20). (d) Amyloid deposition in vessel
walls (Congo-red, ×20).
(a)(b)(c)(d)(a) Osseous metaplasia observed adjacent to amyloid deposition.
Note the single chondrocytes spread in amyloid matrix (asterix) (hematoxlin
eosin, ×10). (b) Areas presenting extensive chondroid
metaplasia (hematoxlin eosin, ×10).
(a)(b)Diagnostic workup including
complete blood count, liver and renal function tests, urine analysis,
esophagography, chest X-ray, electrocardiography, echocardiography, bone-marrow
biopsy, ESR, RF, ANA, and abdominal fat biopsy was carried out.All examinations for exclusion of
systemic amyloidosis, including bone-marrow and abdominal fat biopsies, were
found to be negative for Congo red staining and amyloid deposition. Bone-marrow
aspiration biopsy was found to be free of any type of infiltrations. Thus, the
patient was determined to be free of systemic amyloidosis and diagnosed as
localized, solitary amyloid tumor of the tongue base.Annual examinations were performed in
the four-year follow-up period.


## 3. Comment

The differential diagnosis of the mass in tongue base includes
neoplastic processes and also lingual thyroid. Because the mass was settled
under normal appearing mucosa, a preoperative incisional biopsy was performed
in order to rule out thyroid tissue and malignancy. We could not achieve a
definitive pathology with preoperative biopsy so we planned total excision of
the mass.When amyloidosis is the histopathologic diagnosis in the patients
presenting with a localized mass in head and neck region, the main diagnostic
dilemma of the surgeon becomes the extension of the disease. Many diagnostic
examinations were proposed to rule out a systemic disease. Histopathologic
examinations of these lesions may help clinicians about the necessity of the
diagnostic examinations. Amyloid tumor of tongue base is a rare condition and
may not be predicted preoperatively, therefore there is little information on
the clinical and histopathologic features of the disease. In this paper, we
focused on the clinical and pathological specifications of this rare tumor, so
any unnecessary examinations or measures may be spared and patient may be
informed clearly about the disease.Also, in the literature there is no consensus on terminology of the
disease. We did not prefer to use the term “localized amyloidosis of tongue
base” for this disease because diffuse involvement of tongue with systemic
amyloidosis may be mistaken with well-circumscribed amyloid tumor. The terms
“localized primary amyloid tumor” and “solitary amyloid tumor” were both used
for localized amyloid deposits without systemic amyloidosis or multiple myeloma
in the literature, and better distinguish from the systemic form and better
defines the disease. So we decided to use the term “solitary amyloid tumor” for
the diagnosis after ruling out systemic involvement of the disease because it
briefly underlines the nature of the disease.The definitive treatment of
localized amyloidosis was cited to be surgery. Surgery alone may be 100%
curative [1]. The diagnostic workup of our patient was performed after
histopathological diagnosis. Patient's urine immunofixation was negative for
Bence Jones protein. Bone-marrow examination revealed no evidence of a plasma
cell dyscrasia. Also, abdominal fat biopsy was free of amyloid deposits. To
date, the patient has not developed clinical or laboratory evidence of systemic
amyloidosis or multiple myeloma for a four-year follow-up period.Although, negative staining with
AAC and osseous metaplasia which is noted in histopathological examination
supports non-AA-type amyloidosis, we performed these examinations to support
our diagnosis. Negative staining of amyloid material with AAC is mostly seen in
primary type of amyloidosis. Also, osseous metaplasia noted in the histopathologic
examination may not be thought as definite criteria for localized amyloidosis, but a supporter of
localized, solitary amyloid tumor diagnosis. There is data about osseous
metaplasia in the literature regarding the solitary amyloid tumor of other tissues
[4], and to our knowledge this is the first case in tongue. This osseous
metaplasia correlates with the calcification on computed tomography.A submucosal, surgically well-defined,
well-circumscribed, and rubbery mass in tongue base with calcifications on
radiologic studies may not be surgically differentiated from other tumors of
tongue. When histopathology reveals amyloid deposits on light microscopy, these
clinical findings may come out as important features in order to differentiate
local disease from involvement of tongue by a systemic disease.With this little information
regarding the clinical and histopathologic features of localized, solitary
amyloid tumor of tongue base, we may not discuss the necessity of the
examinations in order to rule out systemic disease including abdominal fat and
bone-marrow biopsy. Therefore, the publication of more cases or series of the
disease may yield better characterization of the histopathologic, radiologic,
and clinical features of solitary amyloid tumor of tongue base.



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