Langerhans cell histiocytosis (LCH) is an abnormal clonal expansion of myeloid dendritic cells. It a rare disease with a prevalence between 2 – 5 cases per million children, primarily between the ages of 5 – 15 years. Abnormal cells can infiltrate various tissues and is classified as single- or multi-system LCH. We present a case of a 12-year-old boy with scalp subcutaneous lymph node LCH. To our knowledge no other case reports of LCH involving a subcutaneous lymph node have been published.
A 12-year-old boy was referred to Plastic surgical department at Middlemore hospital with a 3 x 2cm painful, subcutaneous mass on the left parietooccipital scalp, initially thought to be a pilar cyst. The patient had no other symptoms or other medial illnesses. Examination revealed no other cutaneous lesions or palpable lymphadenopathy. The lesion was excised, and histology results reported as BRAF-negative, LCH within a subcutaneous lymph node.
LCH is a rare, neoplastic disorder with a varied clinical presentation, ranging from self-limiting, localised to disseminated fatal disease requiring chemotherapy. Most tissues can be affected; single system disease usually involves the bone (80%), skin and lymph nodes while multisystem disease can involve one or more organ systems including liver, lung, spleen, and bone marrow, which may progress to organ dysfunction. Being aware of this clinical spectrum is important when patients are referred for management of cutaneous manifestations. These patients should be referred to a paediatric haematologist and the relevant clinical work-up should commence to prevent delays in management and avoid morbidity. These patients should be followed up long-term with the rate of disease reactivation reported to be as high as 30%.