European Journal of Cardiovascular Medicine

Amyloidosis comprises a heterogeneous group of disorders characterized by the deposition of amyloid protein in various target organs of the body. This ultimately leads to organ malfunction and failure1. The term “amyloid” (amylon, in Greek) was coined by the pathologist Virchow, in 1854, to describe the deposits of a substance that he erroneously identified with starch2. The incidence of amyloidosis is estimated between 5 and 13 per million people per year. Amyloidosis involving the upper aerodigestive tract, albeit rare, plays an essential part in the differential diagnosis of clinical situations. In localized amyloidosis of the upper aerodigestive tract, the most frequently involved site is the larynx, followed by the oral cavity and oropharynx.Only 3% of cases are reported to involve the sinonasal cavity and nasopharynx3. Nasopharyngeal amyloidosis has previously been described in the literature in 13 different patients, all of whom had localized amyloidosis4. A diagnostic dilemma can arise from its ability to imitate the appearance of a diverse number of other lesions clinically, which can be definitively distinguished by specialized histopathological examination and ancillary investigations5.

We hereby report 3 cases of amyloidosis which presented to our department at a tertiary care hospital in Central Travancore, Kerala.

Case 1  :  A 54 year old male presented to the outpatient department with complaints of dysphagia and foreign body sensation in the throat since 5 months. The routine blood investigations were within normal limits. On examination, the oropharynx showed a mucosal mass hanging behind the uvula. Serum protein electrophoresis showed a slight decrease in albumin and alpha 2 globulins. No M Band was seen. Nephelometric analysis of serum Kappa and lambda free light chains were raised (2.718) (Kappa>lambda) and the ratio was also raised suggesting a monoclonal gammopathy. Peripheral smear revealed dimorphic anaemia with neutropenia, leucopenia and adequate platelet counts. Bone marrow aspiration showed megaloblastic erythroid hyperplasia along with giant metamyelocytes and only one percent plasma cells. Bone marrow biopsy showed a mildly hypercellular bone marrow. Computed Tomography showed a polypoidal mass with mildly lobulated margins in the nasopharyngeal mucosal space extending partly to the oropharynx. This mass was excised under general anaesthesia and sent for histopathological examination. A single, firm, pale white tissue mass measuring 4 x3x1.5cms was received in our department. On cut section this mass had pale white glistening appearance and pale yellow areas. Microscopically, tissue lined partly by squamous epithelium and partly by pseudostratified ciliated columnar epithelium was seen. Subepithelium showed eosinophilic acellular material with clusters of plasma cells and multinucleated giant cells scattered in-between (Fig 1 )  Focal areas showed mature plasma cells arranged in a diffuse pattern. Immunohistochemistry was strongly immunoreactive for CD138 and Kappa in the neoplastic plasma cells. The eosinophilic acellular material showed positivity with Congo red stain and apple green birefringence under polarised light microscopy (Fig 2a , 2b). Bone marrow biopsy, hematological investigation, plasma/urine electrophoresis, and skeletal survey were unremarkable. Whole body positron emission tomography-computed tomography (PETCT) also didn’t show any evidence of  systemic lesion. A conclusive diagnosis of primary amyloidosis with extramedullary plasmacytoma was made with the above findings.

Case 2   A 43year old lady presented to the out patient department with hoarseness of voice. Examination disclosed a polypoidal swelling of bilateral false vocal cords.  Excision of the lesion was done. Microscopically the lesion was composed of pale eosinophilic acellular material deposition in the stroma (Fig 3), which stained  positive with Congo red stain. Amyloidosis was diagnosed based on pathological examination. There was no evidence of systemic disease or secondary amyloidosis in additional laboratory and imaging studies including complete blood count, liver function, renal function, serum electrophoresis, urine analyses, echocardiography, rheumatoid factor, anti-nuclear factor and abdominal ultrasound.

Case 3 A 38 year old male patient presented to the out patient department with complaints of a gradual change in his voice over the last 5 years which aggravated on voice strain and improved on voice rest. Examination by direct laryngoscopy revealed a right vocal cord polyp. The lesion was excised and sent for histopathology examination. Microscopically the lesion showed homogenous, acellular eosinophilic material in the subepithelial region as well as around the blood vessels and in the stroma (Fig 4a, 4b) . These deposits stained positive with Congo Red stain. The patient was later investigated extensively to rule out any systemic involvement by amyloidosis and all his investigations were within normal limits. Hence a final diagnosis of Primary laryngeal amyloidosis was made.

FIGURES:

CASE 1

Fig 1 Photomicrograph showing pale eosinophilic material surrounded by sheets of plasma cells (Haematoxylin & Eosin  X20)

FIG 2a : Congo red stain showing orange red positivity

Fig 2b : Green birefringence under polarised light

CASE 2

Fig 3 : Tissue lined by pseudostratified ciliated columnar epithelium with deposits of pale eosinophilic material in the subepithelial stroma

CASE 3

Figure 4a : Deposition of eosinophilic acellular amorphous material in the sub epithelial stroma

Fig 4b : Eosinophilic material in the sub epithelial stroma showing Congo red positivity.

Amyloidosis  is  a  rare  benign  disease  characterized  by extracellular  deposition  of  proteinaceous  material  in  the targeted  tissue, which  has  typical staining  properties  and electron microscopic appearance. The hallmark of this deposit is its apple green birefringence visible under polarized microscopy. Under the  electron  microscope,  amyloid  appears  as  a  mass  of rigid,  non-branching  fibrils.   X-ray    crystallography reveals that these fibrils have a regular, antiparallel, beta-pleated sheet configuration6.

 Amyloidosis can be categorized as hereditary, primary (when it develops spontaneously), or secondary (secondary to an infectious or chronic inflammatory disease). Primary amyloidosis is further subclassified into a localized form where deposits are seen in a single location or organ such as the larynx, or a generalized form in which the deposits are widespread. Biochemical classification is based on the type of protein deposited, with around 25 types identified till date. The commonest among these (in descending order) are the AL (Light chain) type derived from plasma cells containing kappa and lambda immunoglobulin light chains associated with myelomas, amyloid associated (AA) type which is a non-immunoglobulin protein synthesized in the liver and found in systemic amyloidosis and the amyloid-beta (AB) type with beta-2 microglobulin deposits usually seen in Alzheimer’s disease and hemodialysis associated amyloidosis5.

Amyloid deposition in the upper aerodigestive tract generally arises without any systemic involvement. It is reported that only 15% of laryngeal amyloidosis cases have systemic involvement. Nevertheless, a routine workup is considered obligatory to rule out a systemic disease or other associated neoplasms3. This  includes a search for lymphadenopathy, radiographic imaging (chest x-ray, skeletal survey, urinary and digestive tract evaluation), electrocardiogram, peripheral blood smear examination, complete blood count, bone marrow biopsy, tissue assessment for systemic amyloid, and clinical laboratory studies (erythrocyte sedimentation rate, liver chemistries, renal function studies, quantitative immunoglobulin assay, serological test for rheumatoid arthritis, urine analysis, urine and/or serum electrophoresis, Bence-Jones protein analysis) has been suggested to ascertain the true nature of the process. Furthermore, as indicated clinically, a rectal, lip, gum, kidney, spleen, liver, endomyocardial, skin, or small-bowel biopsy and/or abdominal fat aspirate may be performed to exclude systemic disease. An endoscopic examination of the aerodigestive tract may also be necessary, given the high incidence of multifocal involvement by the disease.

Amyloidosis usually presents in adults, though reports in pediatric patients are also documented. Male or female predominance has also been documented in many studies10.Among our cases all were adults aged 38, 43 and 54 years. One patient among them was a lady while the other two were male patients.

Deposition of amyloid protein in different locations of the head and neck can cause hoarseness, a foreign body sensation in the pharynx, dysphagia, cough, and nasal obstruction7. In our case the patient who had nasopharyngeal amyloidosis presented with dysphagia and foreign body sensation whereas the patients who had laryngeal amyloidosis presented with hoarseness and change in voice.

Extramedullary plasmacytomas (EMPs) consist only 3% of all plasma cell tumors .Although they can be found anywhere in the body, over 80% are found in the head and the neck region. Rarely, they may be associated with amyloid deposits. One of the most common forms of amyloid protein is light chain protein which is derived from plasma cells and, hence, there is a pathogenic relationship between plasma cell neoplasms and amyloid. Although slow growing and localized EMPs can be closely associated with, or may progress to multiple myeloma, hence, an early diagnosis and regular follow-up is essential. Treatment options are surgery and/or radiation either singly or in combination.8 In our case, the patient presented with a nasopharyngeal mass extending into the oropharynx. Histopathological examination showed extensive plasma cell infiltration as sheets with areas of eosinophilic acellular material and interspersed giant cells with plasma cells being immunoreactive for CD138 and Kappa light chain pointed to a diagnosis of extramedullary plasmacytoma with amyloidosis. Even in the present case, only multiple deeper sections of the tumour revealed the localised plasma cell infiltrate. Thus the association between amlyloidosis and plasmacytoma albeit rare is highlighted. On further investigations the patient did not have any evidence of systemic plasma cell dyscrasias or amyloidosis. Treatment approaches include surgery, radiation, chemotherapy either singly or in combinations. All cases of EMPs of the head and the neck region justify regular and a long-term follow-up with the otorhinolaryngologists and hematologists owing to their unpredictable outcomes. Monitoring of all cases for a period of up to 5 years is warranted in most cases8. The tumor was excised in its entirety in our cases with postoperative radiation for residual disease and to reduce chances of recurrence. Our patient is now on regular follow up and is currently asymptomatic.

Our other two cases were those of laryngeal amyloidosis , both of which did not show any evidence of systemic involvement. Two theories have been postulated to explain the occurrence of localized or isolated laryngeal amyloidosis. The first suggests a plasma cell reaction to inflammatory antigens giving rise to amyloid deposits. This theory was supported by pathologic studies showing the presence of mixed polyclonal plasma cells interspersed with the amyloid tissue. Second theory points to the inability of the body to clear the light chains produced by plasma cells located in the mucosal-associated lymphoid tissue. There does not seem to be a specific location in the larynx that is more frequently affected by amyloidosis; instead, all parts of the larynx can be affected. Many cases reported in the English literature also document multifocal or systemic amyloidosis but only rarely was a true B-cell neoplasm documented9. None of our cases had documented serum or urine electrophoretic abnormalities, and none of our patients developed multiple myeloma or an overt B-cell malignancy. LA seems to be an indolent process, with patients living a long time with evidence of recurrent disease. Even patients who died with disease were alive for more than 10 years after their initial presentation. Therefore, it is important to have sustained and regular long-term follow-up of these patients to assess accurately the disease progression9.Our patients are on continued surveillance and have not shown any symptoms of progression of the disease.

The differential diagnoses are hyalinized vocal cord polyp and lipoid proteinosis. The special stains for amyloid will help to differentiate these entities. Amyloidosis can occur in association with other conditions as well such as laryngeal neuroendocrine tumors including small cell carcinoma and medullary carcinoma of the thyroid. It is important to consider and exclude the possibility of these conditions when a case of amyloidosis of the larynx is encountered.

Other differential diagnoses to be considered include plasma cell granuloma, multiple myeloma and a spectrum of B cell lymphomas with plasmacytic differentiation like marginal zone lymphoma (MZL) and lymphoplasmacytic lymphoma (LPL). However the lack of a myeloma defining event along with absence of hyperviscosity symptoms, lack of mucosal and splenic involvement along with non-reactive immunohistochemistry for CD 20 ruled out all the above possibilities

For treatment in the larynx, a conservative approach has been recommended consisting of local excision using laser or microlaryngeal instruments with conservation of surrounding tissue. Recent literature has advocated CO2 laser as the treatment of choice. Recurrence is rare, and, if it occurs, can be treated with further conservative excision12.

Amyloidosis of the head and neck is rare entity which may be overlooked many a times. A high index of suspicion of an underlying plasma cell neoplasm needs to be considered when encountering localised amyloid deposits in the head and neck region as studies have reported such instances even in children. Although the possibility of a systemic disease is low, appropriate clinical, radiographic, and laboratory investigation to rule out systemic disease and to subclassify correctly the form of amyloidosis is recommended.. While the prognosis for localized amyloidosis is good and it generally behaves in a benign fashion, regular and long term follow-up is important in view of chances of recurrence and  a progression to the systemic form although rare.

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