Neck masses in children — formative SAQs

SAQ 1 (10 marks)

A 3-year-old boy is brought by his parents with a four-week history of a painless lump in the right side of the neck. He is otherwise well, feeding normally, with no fever, weight loss or night sweats. On examination there is a 2.5 cm firm, non-tender mass in the right anterior triangle of the neck, with overlying skin that has a faint violet-grey discolouration. He is afebrile and systemically well. [1] [3]

1. What is the most likely diagnosis, and which two features of the history and examination support it? (3) [3]
2. Outline your investigation and management plan, naming the first-line imaging test and the definitive treatment. (4) [2] [3]
3. Describe the key pitfall to avoid and how you would distinguish this from tuberculous lymphadenitis. (3) [3]

Model answer — SAQ 1

(1) Diagnosis (3). The most likely diagnosis is non-tuberculous mycobacterial (NTM) cervicofacial lymphadenitis. The two supporting features are the classic age and behaviour — an otherwise well child aged one to five years with a chronic (four-week), unilateral, painless, slowly enlarging cervical node and minimal or no systemic upset — and the characteristic violet-grey discolouration of the overlying skin, which is a hallmark of NTM lymphadenitis as the granulomatous process thins and discolours the skin. This is one of the commonest chronic cervical masses in the young-child age band. [3] [1]

(2) Investigation and management (4). The first-line imaging test is ultrasound, which confirms the nodal mass, defines its architecture and excludes abscess formation or an underlying congenital cyst. The definitive treatment, as set out by the International Pediatric Otolaryngology Group consensus, is complete surgical excision. Medical therapy with a clarithromycin-based multidrug regimen is reserved for the case in which complete excision would endanger the facial nerve or skin, or for residual or recurrent disease. I would refer the child to paediatric otolaryngology for surgical planning rather than aspirate or drain the node. [2] [3]

(3) Pitfall and distinction from tuberculosis (3). The key pitfall is incision and drainage under the impression that the node is a pyogenic abscess, which in NTM disease creates a chronic discharging sinus and makes subsequent management far harder — the correct treatment is complete surgical excision. To distinguish NTM from tuberculous (TB) lymphadenitis, I would use a tuberculin skin test or interferon-gamma release assay, a chest radiograph, and aspiration or biopsy for acid-fast bacilli, mycobacterial culture and polymerase chain reaction: TB lymphadenitis typically shows a positive IGRA or strongly positive tuberculin test with systemic or contact-history features and is treated with standard antitubercular therapy, whereas NTM disease occurs in an otherwise well child with a normal chest radiograph and is treated surgically. [3]

SAQ 2 (10 marks)

A 15-year-old girl presents with a six-week history of a painless lump in the left supraclavicular fossa. She describes intermittent drenching night sweats for three weeks and has lost 3 kg in weight. On examination there is a 3 cm, firm, non-tender, fixed node in the left supraclavicular fossa. She is afebrile but looks pale. [1] [5]

1. What is the most likely diagnosis, and why is the location of this node specifically alarming? (3) [5] [1]
2. Outline your immediate investigation and referral plan. (4) [2] [5]
3. Discuss the red flags for malignancy in a paediatric neck mass and the four-to-six-week rule. (3) [1]

Model answer — SAQ 2

(1) Diagnosis and the alarm of the location (3). The most likely diagnosis is lymphoma — most likely classic Hodgkin lymphoma given the adolescent age. The location is specifically alarming because a node in the supraclavicular fossa is pathologic until proven otherwise: the supraclavicular nodes drain the thorax, abdomen and pelvis, so a malignant supraclavicular node is often a sentinel of lymphoma or of metastatic disease from a distant primary. Combined with the constitutional B symptoms (night sweats, weight loss) and the pallor (raising anaemia), this picture is lymphoma until excluded. [5] [1]

(2) Investigation and referral (4). The first investigation is ultrasound of the neck to characterise the node, followed by tissue sampling — an ultrasound-guided core biopsy or, if lymphoma is suspected (as it is here), an excisional biopsy of an intact node for histology, immunohistochemistry, flow cytometry and molecular studies, because intact nodal architecture is needed for accurate lymphoma subtyping. I would obtain a full blood count, film, inflammatory markers and lactate dehydrogenase, and an early chest radiograph to look for a mediastinal mass. I would refer urgently to paediatric oncology for staging (which would include cross-sectional imaging of the neck, chest, abdomen and pelvis) and protocol therapy, and not prescribe further empirical antibiotics or steroids before biopsy, as steroids can obscure the histology. [2] [5]

(3) Red flags and the four-to-six-week rule (3). The red flags for malignancy in a paediatric neck mass are a hard, fixed, painless, progressively enlarging node; a node in the supraclavicular fossa or posterior triangle; a node larger than two to three centimetres or matted to surrounding tissue; the constitutional B symptoms of unexplained fever, drenching night sweats and weight loss; and any node that persists or grows beyond four to six weeks or fails to respond to a course of antibiotics. The four-to-six-week rule states that a node persisting beyond four to six weeks — or earlier if any of the other red flags are present — must be investigated with ultrasound and tissue sampling rather than treated empirically a second time, because benign reactive nodes resolve. Applying this rule is how the malignant node is found early rather than late. [1]