April 9, 2005
Lymphoma Mimicking a Thyroglossal Duct Cyst in an Adolescent
Mass lesions of the head and neck in infants and children can be either developmental, inflammatory or neoplastic. Lymphomas (Hodgkin's or Non-Hodgkin's) commonly present as neck lumps in children. Although malignancy is not the commonest aetiology of paediatric cervical lumps, a high index of suspicion is critical to facilitate early diagnosis and treatment of cervical lesions. We present the case of a 15-year-old boy who presented with a solitary midline cervical lesion, which simulated a thyroglossal cyst on clinical examination. However, histopathological examination revealed it to he a Hodgkin's lymphoma. Related literature is also reviewed.Key words: Adolescent; Hodgkin's Disease; Neck; Thyroglossal Cyst
The cervical region is a common site for a number of mass lesions, most of which are, in children, of developmental or inflammatory origin. Although malignancy is not the most common aetiology, cervical lumps in infants and children must be considered possibly malignant until proven otherwise.
With the exception of rhabdomyosarcomas of the nasal passages and orbit and, rarely, neuroblastomas that present in the cervical region, malignant lesions tend to present later in childhood or in the teenage years. Congenital and inflammatory lesions, on the other hand, present in infancy and early childhood.
An accurate history and physical examination combined with other diagnostic modalities, such as biopsy or an imaging scan, will usually establish the diagnosis.
Neoplasms involving the head and neck account for 5 per cent of all malignancies occurring in children.1 More than 50 per cent are lymphomas (Hodgkin's lymphoma (HL) or non-Hodgkin's lymphoma (NHL)) or soft tissue sarcomas, primarily rhabdomyosarcomas.1 The American Cancer Society estimates that in 2002 there were about 7000 new cases of Hodgkin's disease in the USA.2
The most common presentation of HL is a painless, firm, fixed cervical mass. The commonest site for presentation is the neck, although deposits may be also found in the mediastinum, liver and bone marrow.
A 15-year-old boy presented to our department with nine months history of a swelling in the neck. Initial blood tests requested by his general practitioner were normal. Examination of the lump revealed a 1.5-cm, round, non-tender lesion in the midline at the level of the hyoid bone with a firm consistency. The lump was mobile on protrusion of the tongue and swallowing. There were no other lumps in the neck and the rest of the examination was unremarkable. The past medical history was also unremarkable.
Ultrasound examination of the neck revealed a 1.6-cm diameter, ovoid soft tissue mass, superficial to the lower mylohyoid, lying just superior to the hyoid bone. The fact that the mass was lying superficial to the mylohyoid and did not penetrate it did not favour the diagnosis of a thyroglossal cyst. Fine needle aspiration was then carried out. Mucoid material was aspirated.
Histopathological examination of the specimen revealed only blood and lymphoid cells consistent with origin from a lymph node.
Following this, the patient underwent a Sistrunk operation. However, on dissection, there was no evidence of a tract-connection between the lesion and the tongue base; therefore, no dissection of the hyoid bone was carried out. The lesion was sent for histopathological examination, which showed a lymph node in which there was marked expansion of the interfollicular zone and effacement of the architecture (See Figure 1). There was an infiltrate of large atypical cells within the lymph node, some of which were multilobulated, whilst others resembled Reed-Stenberg cells (See Figure 2). These histological appearances were consistent with lymphocyte predominant HL.
Computed tomography (CT) scan of the thorax, abdomen and pelvis did not show any pathology. The patient was subsequently treated with chemotherapy.
Cervical lesions are commonly encountered in the paediatric population. In children, in contrast to adults, most cervical lesions are benign. There are three basic classifications: congenital, inflammatory and neoplastic lesions. On a review of 445 cases, 55 per cent of all cases were found to he of congenital origin, 27 per cent of inflammatory origin, and 14 per cent due to neoplasia.3
A lymph node in which the normal follicular architecture has been effaced (H&E, 20).
A typical Reed-Stenberg cell of Hodgkin's disease in a background of small lymphocytes (H&E, 400).
Congenital lesions are common and may include cystic hygromas, haemangiomas, branchial cleft anomalies, thyroglossal duct cysts, and dermoid and epidermoid cysts. In their series review of 102 cases Nicollas et al. reported an incidence of 53.4 per cent for thyroglossal cysts and 11 per cent for dermoid cysts, as the most common midline cervical abnormalities.4 Inflammatory lesions are also commonly encountered and mainly involve lymph nodes. They can be due to a bacterial or a viral cause or, less frequently, to an atypical mycobacterial infection. Malignant lesions include lymphomas, thyroid carcinoma, rhabdomyosarcoma and neuroblastoma.
The differential diagnosis of a thyroglossal duct cyst includes ectopic thyroid tissue, thyroid neoplasms, dermoid or sebaceous cyst, lipoma and submental lymphadenitis. Malignant transformation or malignancy within the cyst is a clinical entity well described in the literature. It is either of thyroid or squamous cell origin, with thyroid papillary carcinoma appearing as the most common form (80 per cent of the cases).5 Ectopic thyroid tissue is identified within the cysts in about 25 to 35 per cent of all cases.1
Dermoid cysts may appear in the midline of the neck and therefore be confused with a thyroglossal duct cyst.6 Other, less common cervical lesions which should be included in the differential diagnosis are pyriform sinus lesions, cervical teratomas, lung herniation, venous aneurysms, torticollis, ranula and midline cervical cleft.
Thyroglossal duct cysts are ectodermal remnants which develop along the line of descent of the thyroid gland from the base of the tongue to the pyramidal lobe of the thyroid gland. They are the most common congenital neck masses. Thyroglossal cysts are more commonly encountered in children between two and 10 years of age, with equal prevalence in both sexes.1 Classically, they are located in the midline at, or immediately adjacent to, the hyoid bone. These cysts are usually soft, smooth and non-tender, and, owing to their attachments to the foramen caecum and hyoid bone, they may rise in the neck when the child swallows or protrudes its tongue, although this is not a consistent finding.
When considering preoperative imaging there does not appear to be a consensus about a single most useful diagnostic modality. Ultrasonography appears as the study of choice for the diagnosis of midline masses, with 10 per cent sensitivity and 95 per cent specificity for detecting thyroid gland tissue.7 It is also of value in the differential diagnosis of masses in the anterior neck region, being especially useful for distinguishing between a thyroglossal duct cyst, a fluid-filled laryngocele and a branchiogenic cyst.8 In the UK the commonest preoperative imaging investigations requested are the ultrasound scan and the radioisotope scan.9 The possibility of the patient's only functioning thyroid tissue being removed due to being mistaken for a thyroglossal cyst may thus be avoided.
Thyroglossal duct cysts are best treated by complete excision of the cyst, following its sinus tract up to the base of the tongue and including removal of the central portion of the hyoid bone, as described by Sistrunk in 1920.10
Neoplasms of the head and neck region account for 5 per cent of all malignancies occurring in children.1 More than half of these are lymphomas (HL or NHL) or soft tissue sarcomas.1 A malignant lymphoma is a neoplastic transformation of cells that reside in lymphoid tissue. The two main variants are NHL and HL. Both forms typically appear with painless adenopathy, and thus frequently present to the head and neck surgeon.
The type of malignancy encountered differs with age. In adolescents HL is more common.1
Although fine needle aspiration (FNA) of head and neck masses is used routinely in adults, it is not used commonly in children. However, Ramadan et al. showed that FNA in children is a well tolerated method. No complication was noted, and no false negative or false positive results were encountered. In one patient FNA was nondiagnostic and the diagnosis was established after surgical biopsy.11 On comparing FNA with diagnostic open biopsy, FNA reduces the need for more invasive and costly procedures, with potential complications. However, FNA has limitations, as in cases of nonhomogeneous masses or in cases where the histological architecture of the sample needs to be preserved.12
Formal excisional biopsy is preferred over needle biopsy in rapidly enlarging masses, in the presence of systemic symptoms, and when repeated FNA cytology is nondiagnostic. Excisional biopsy ensures that adequate tissue is obtained, both for light microscopy and for appropriate immunocytochemical studies, culture and cytogenetic analysis.
In reviewing the literature, there has been only one other published case \of HL simulating a thyroglossal cyst in a paediatric patient. This was a case of a 14-year-old boy with Robin sequence who presented initially for evaluation of an enlarging lump beneath his chin. As the clinical impression was that of a thyroglossal cyst, surgical excision of the lump was performed and histopathological examination revealed HL of lymphocyte predominance type. However, in this case the lymphoma was more extensive, with deposits in femoral and submandibular lymph nodes. The patient was treated with involved field irradiation and combination chemotherapy with ABVD and MOPP.13
In our case we demonstrated that although ultrasound scanning remains the most commonly used clinical investigation, definitive diagnosis of the cervical lesion was established only after an excisional biopsy. Although the lesion demonstrated all the cardinal clinical features of a thyroglossal duct cyst, the final diagnosis was that of HL. Therefore, emphasis should be placed by an examining physician on early referral for specialist opinion, despite initial clinical examination indicating a benign lesion.
Although malignancy is not the commonest aetiology of paediatric cervical lumps, a high index of suspicion is critical to facilitate early diagnosis and treatment of cervical lesions. The role of the ENT surgeon remains central in the management of head and neck masses and should be the first point of referral by the general practitioner. A thorough ear, nose and throat examination is mandatory. Ultrasonography can be a useful adjunct in evaluating lesions of the head and neck.
Each lesion has to be evaluated by FNA and excision biopsy under a general anaesthetic. Hodgkin's disease is a rare malignancy, accounting for one in four of all lymphoma cases. A multidisciplinary approach is needed for the management of the paediatric patient with Hodgkin's disease, involving the ENT surgeon, a paediatrician, an oncologist, and a radiologist.
We would like to thank Dr N Williams, Consultant Pathologist, Singleton Hospital, Swansea, UK, for his contribution of the photomicrographs.
* Midline neck swelling in adolescents is usually due to a thyroglossal cyst
* In this case a midline neck swelling was the presentation of Hodgkin's lymphoma, diagnosed by histological examination of the resected lesion
* Ultrasonography appears to be the imaging modality of choice with midline neck swelling
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10 Sistrunk WE. The surgical treatment of the thyroglossal tract. Ann Surg 1920;71:121-4
11 Ramadan HH, Wax MK, Boyd CB. Fine-needle aspiration of head and neck masses in children. Am J Otolaryngol 1997;18:400-4
12 Liu ES, Bernstein JM, Sculerati N, Wu HC. Fine needle aspiration biopsy of Pediatric head and neck masses. Int J Pediatr Otorhinolaryngol 2001 20;60:135-40
13 Good GM, Isaacson G. Hodgkin's disease simulating a Pediatric thyroglossal duct cyst. Am J Otolaryngol 2000;21:277-80
ANDREW TARNARIS, MRCS, WIJAYASINGAM GIRIDHARAN, FRCS, DAVID W AIRD, FRCS
From the Department of ENT Surgery, Singleton Hospital, Swansea, Wales, UK.
Accepted for publication: 11 October 2004.
Address for correspondence:
Dr Andrew Tarnaris,
3 Sawel Terrace,
Carmarthenshire SA4 0UY,
Fax: +44 (0)1792 884702
Dr A Tarnaris takes responsibility for the integrity of the content of the paper.
Competing interests: None declared
Copyright Royal Society of Medicine Press Ltd. Mar 2005