Main causes of cervical lymphadenopathy are an infection or neoplastic infiltration. The latter may consist of secondary deposits from a primary tumour elsewhere in the body or be primary in nature, i.e. lymphoma.
Infective conditions may be viral or bacterial, acute or chronic. Examples include tonsillitis, infectious mononucleosis, acquired immunodeficiency syndrome, scalp infestations and cat-scratch fever. Pyogenic infections (usually staphylococcal in nature) may form large painful abscesses that require drainage. Cervical cellulitis due to streptococcal infection is fortunately rare nowadays. As the infection is confined by the deep cervical fascia, airway obstruction from pressure and laryngeal oedema can occur in these patients.
Although rare in western countries, tuberculosis of the cervical lymph nodes (Mycobacterium tuberculosis) is common in developing countries and is encountered in the West in immigrant populations. Tuberculous cervical lymphadenopathy results in a collar-stud abscess. In western countries infection is more commonly caused by atypical mycobacteria, also known as MOTT (mycobacteria other than typical tubercle). These infections are nowadays most often encountered in patients suffering from AIDS.
Lymphomas and causes of cervical lymphadenopathy
The neck forms one of the most common sites for lymphoma, a primary tumour of lymph nodes. Lymphoma is classified into two broad categories, Hodgkin’s, non-Hodgkin’s lymphoma, each category being subdivided into various types depending on the cell of origin of the tumour (T or B cell) and the degree of differentiation. When it arises in the neck, the tumour forms painless non-tender swellings. The enlarged lymph nodes are discrete, firm and rubbery and may be located in either the anterior or posterior triangles. When enlarged nodes are discovered in the neck, a systematic palpation of other lymph node sites (axillary, inguinal) and palpation of the abdomen for enlarged liver and spleen are essential to determine whether the disease appears to be localized to one region or has disseminated. The patient may or may not have systemic symptoms such as malaise, intermittent fever and weight loss. The staging of lymphomas, necessary for outlining the treatment regimen, necessitates the performance of special investigations including radiology of the chest, computed tomography, isotope bone scan and bone marrow biopsy. Within each stage, the absence or presence of systemic symptoms is designated by the letters A and B respectively.
Metastatic cervical lymphadenopathy
Overall, metastatic deposits in one or more cervical lymph nodes constitute the most common cause of a lump in the neck. The common sites of primary tumours that may present in this way are pharynx and larynx (squamous cell carcinomas), oral cavity (tongue, buccal mucosa), thyroid, bronchus, breast and upper digestive system (oesophagus, stomach, pancreas). The deposits may occur anywhere in the neck but the most common sites are the deep cervical and supraclavicular regions, especially on the left side. Metastatic nodes are always hard in consistency and soon become fixed to surrounding tissues and matted together, although in early disease the enlarged nodes may be mobile on palpation. There is an important sequence of investigations whenever enlarged lymph nodes thought to be caused by secondary deposits are found in the neck, with no other apparent abnormality on complete physical examination.
It is very important that this protocol is followed before the lump is submitted to biopsy, since if the primary tumour is in the head and neck (usually squamous in nature), cervical block dissection of the enlarged lymph nodes is required together with excision of the primary. The success of this treatment is jeopardized if a preliminary excision biopsy of the involved nodes has been carried out.