Non-hodgkin lymphoma, head and neck manifestation

(Thomas Hodgkin, 1798 - 1866, English physician), the third most frequent malignant tumour in the head and neck, after basal cell carcinoma of the skin and mucosal squamous cell carcinoma head and neck. It is a heterogeneous group of neoplasms originating from lymphocytes or their derivatives. Non-Hodgkin lymphoma has varying clinical presentations and different courses and prognoses.Various classifications have tried to predict the outcome of these tumours. The Working Formulation of non-Hodgkin lymphoma divides it into three prognostic categories (low, intermediate and high grade lymphomas), based on architectural features (follicular or diffuse involvement) and cytological features.

Non-Hodgkin lymphoma is a disease of the middle-aged and elderly, with only few cases occurring before the age of 40. It represents about 5% of head and neck malignancies. About 11% of non-Hodgkin lymphomas present with lesions in this region, and about 50% of patients with head and neck disease have systemic disease.

Non-Hodgkin lymphoma can involve virtually any site in the extracranial head and neck. Nodal involvement is common, but in several studies extranodal spread is reported to occur more frequently than nodal enlargement. In the head and neck, two distinct extranodal sites are recognized: extranodal lymphatic spread or involvement of Waldeyers ring, and extranodal extralymphatic spread.

Diagnostic imaging

Radiological differentiation between squamous cell carcinoma and non-Hodgkin lymphoma of the ring of Waldeyer is difficult, especially when there is extension outside the tonsils. Findings suggesting the correct diagnosis are multiple noncontiguous sites of disease (rarely seen in squamous cell carcinoma) and an association with large, non-necrotic lymph nodes, especially when they are bilateral and in unusual draining routes for squamous cell carcinoma (Fig.1). The diagnosis of non-Hodgkin lymphoma is strongly suggested if there is an association between a lesion in the ring of Waldeyer and an extralymphatic lesion.

Extranodal extralymphatic non-Hodgkin lymphoma occurs most commonly in the sinonasal cavities and orbits, but it may infiltrate any tissue of the head and neck, such as the deep spaces (Fig.2), skeletal structures, larynx (Fig.3) and thyroid gland (see thyroid gland (VI:2), Fig. 1). Whenever an infiltrating mass is present in the extracranial head and neck region, lymphoma is a possible cause. Radiological differentiation from other diseases, such as pseudotumour and Wegeners granulomatosis head and neck manifestation is usually not possible.

Sometimes a non-Hodgkin lymphoma presents as an isolated mass in the fossa canina, just anterior to the maxillary sinus; however, such a lesion is more likely to arise from an infraorbital lymph node, part of the facial lymph node group. This facial lymph node group further includes the zygomatic node, buccal nodes and mandibular node, all of which may become involved by non-Hodgkin lymphoma.

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