Ultrasonography of the tongue in macroglossia - a case report.

This paper is an attempt to assess the usefulness of ultrasonography in the diagnosis of the enlargement of the tongue (macroglossia). The role of sonography in diagnosing local pathologies of the tongue, such as neoplasms, abscesses or granulomas, has been well-established for 20 years. Rarely is its usefulness considered with respect to diagnosing macroglossia with concomitant systemic diseases. The starting point of these considerations was the presented case of a 59-year-old patient with considerably enlarged tongue. The patient had difficulty speaking and ingesting meals. Moreover, he complained about swelling and pain in the carpal and proximal interphalangeal joints. Tongue ultrasound examination revealed blurred lingual structure with evident, irregular vascular pattern in the color Doppler. The obtained image helped to rule out local pathology of the tongue and directed our diagnostic considerations towards immunoglobulin-related diseases (deposition diseases). We believe that the presented ultrasound image of the tongue was helpful in the diagnostic process. Establishing the final, correct diagnosis was a particularly strenuous process. The suspicion of a deposition disease had been rejected during two previous stays in two hospitals. This was the consequence of a negative diagnostic test of staining tissue deposits with Congo red. An accurate diagnosis occurred to be a rare form of a deposition disease: lambda light chain disease with symptoms of amyloidosis. Such a diagnosis was based on a thorough hematological analysis. A high level of free lambda light chains in the serum was detected and the bone marrow biopsy showed 13% of plasma cells. The patient underwent chemotherapy.

A man, aged 59, was admitted to the Clinic due to a considerable tongue enlargement which rendered speaking and eating difficult (fig. 1). Such a condition had lasted for approximately 1.5 years – the patient had been diagnosed due to this problem in two other hospitals. At that time amyloidosis was suspected but the diagnosis was rejected since both the specimens obtained from the tongue and subcutaneous adipose tissue gave negative results after amyloid staining. What is more, the patient complained about swelling and pain in the carpal and proximal interphalangeal joints. Ultrasound (US) examination of the enlarged tongue was performed by means of Acuson Sequoia 512 apparatus with a linear probe with the frequency of 7.5–13 MHz (fig. 2). An abnormal lingual structure was visualized with blurred pattern of muscles (fig. 3A). Color Doppler imaging demonstrated enhanced and irregular perfusion (fig. 3B). Additional examinations revealed a very high concentration of free lambda light chains: 6670 mg/L (N: 5.71–26.3 mg/L) and a normal level of free kappa light chains: 9.1 mg/L (N: 3.3–19.4 mg/L). Moreover, serum protein immunoelectrophoresis demonstrated monoclonal lambda light chains. During hospitalization, an aspiration biopsy of the bone marrow was performed. The cytological examination showed a pool of 13% of plasma cells. Furthermore, immunophenotyping disclosed approximately 2.7% of CD38+++ cells with the phenotype: CD138+, CD56+, CD19- and CD45-. These cells were clonal in nature (s+c kappa-, s+c lambda+). The diagnosis of AL amyloidosis, lambda light chain disease was established. In the Hematology Clinic, the patient underwent a therapy with the use of vincristine, doxorubicin and dexamethasone.

Fig. 1

Macroglossia in AL amyloidosis

Fig. 2

Scanning technique

Fig. 3

A. B-mode ultrasound examination – tongue in the sagittal view: blurred image of the lingual muscles. B. Rich net of blood vessels in color Doppler examination

Discussion

Ultrasound assessment of the tongue is difficult due to its complex structure. The tongue is composed of four pairs of extrinsic muscles, which are attached to the surroundings, and four pairs of intrinsic muscles, so-called tongue's own muscles. The strongest extrinsic muscle is the paired genioglossus which is flat and has a triangular, fan-like shape. The tongue may be examined by ultrasounds extraorally through the floor of the oral cavity or intraorally(.

Ultrasound examinations have been used to assess tongue pathologies for over 20 years. The majority of reports concern lingual neoplasms. US examination allows for accurate diagnosis of the neoplastic process in the tongue and it reliably determines the extensiveness of such lesions(.

Moreover, there are a few publications available in medical literature which demonstrate the usefulness of US imaging in assessing inflammatory tumors of the tongue associated with the presence of a foreign body as well as its usefulness in a pathology as rare as a lingual abscess(.

This paper constitutes an attempt to determine the diagnostic value of US imaging in the case of highly advanced, generalized macroglossia. The presented patient with AL amyloidosis manifested abnormal ultrasound presentation of the tongue with blurred image of its muscles. In the normal presentation, two zones may be distinguished. The first is a zone of so-called tongue's own muscles, which is an area whose structure resembles a parenchymal organ. Such echostructure is a result of the complexity of four pairs of intrinsic lingual muscles which are composed of superior, inferior, longitudinal, vertical and transverse fibers. The second zone corresponds to the extrinsic muscles. The largest of them is the paired genioglossus. When normal, it may be easily visualized in the longitudinal view in the central and anterior parts of the tongue as a characteristic muscular structure of a fan-like shape. The Doppler examination of our patient revealed a pronounced but distorted vascular pattern.

Such US presentations allowed for ruling out local lingual pathologies. This was of considerable relevance in the view of such an extreme macroglossia, which was a diagnostic challenge for us, as such images narrowed the diagnostic field to systemic causes, i.e. to a, so-called, metabolic macroglossia that may develop in the course of amyloidosis, acromegaly and hypothyroidism.

A complicated diagnostic pathway of our patient certainly resulted from a rare cause of macroglossia, i.e. primary amyloidosis with plasmacytic dyscrasia(. In this rare situation, we also observed another rare case of light chain deposition disease. It is different from AL amyloidosis in one important aspect. Namely, Congo red staining of extracellular tissue deposits gives negative outcomes. In this disease entity, tissue deposits in affected organs are non-fibrillar in nature. Only tissue deposits of protein fibrils, when stained with Congo red, give such a significant diagnostic sign of apple-green birefringence seen under a polarization microscope. The negative outcome of Congo red staining had surely inhibited and delayed the accurate diagnosis.

The disease was finally identified based on a thorough hematological analysis. However, we hold a belief that ultrasound images of the tongue that we obtained were diagnostically relevant since they directed our search for the reason of macroglossia to the area of hematological deposition diseases.