Erythema nodosum revealing parathyroid carcinoma

Erythema Nodosum: A Practical Approach and Diagnostic Algorithm

Erythema nodosum is the most common form of panniculitis and is characterized by tender erythematous nodules mainly in the lower limbs on the pretibial area. The exact cause of erythema nodosum is unknown, although it appears to be a hypersensitivity response to a variety of antigenic stimuli. Although the etiology is mostly idiopathic, ruling out an underlying disease is imperative before diagnosing primary erythema nodosum. Erythema nodosum can be the first sign of a systemic disease that is triggered by a large group of processes, such as infections, inflammatory diseases, neoplasia, and/or drugs. The most common identifiable causes are streptococcal infections, primary tuberculosis, sarcoidosis, Behçet disease, inflammatory bowel disease, drugs, and pregnancy. We propose a diagnostic algorithm to optimize the initial work-up, hence initiating prompt and accurate management of the underlying disease. The algorithm includes an initial assessment of core symptoms, diagnostic work-up, differential diagnosis, and recommended therapies. Several treatment options for the erythema nodosum lesions have been previously reported; nevertheless, these options treat the symptoms, but not the triggering cause. Making an accurate diagnosis will allow the physician to treat the underlying cause and determine an optimal therapeutic strategy.

Rheumatic manifestations of cancer

Taken together, the wide range of rheumatic and musculoskeletal conditions that can appear in association with cancer emphasizes that rheumatic disease is a major component of the spectrum of paraneoplastic manifestations. Although the pathogenetic mechanisms by which neoplasia causes these manifestations are only partially understood in select cases, it appears that many result from immune-mediated effects stimulated by tumor antigens of endocrine factors produced by tumors. The broad overlap in signs and symptoms of occult malignancy and systemic rheumatic disease, as well as the occurrence of distinct localized and systemic musculoskeletal and rheumatic syndromes in the presence of cancer, emphasizes the importance of considering and investigating the possibility of occult malignancy in the evaluation of patients with these symptoms. This is particularly important in older patients, those with atypical rheumatic disease, and those who do not respond appropriately to conventional immunosuppressive therapy.