Rare manifestations of sarcoidosis

Abstract

Sarcoidosis may be associated with granulomatous inflammation in any part of the body, usually in more than one area [1]. Rare manifestations of sarcoidosis include unusual patterns of organ involvement, or are the result of granulomatous inflammation developing in unusual locations for sarcoidosis. In other rare cases, sarcoidosis is associated with a second disorder. Although the frequency of individual rare manifestations is by definition low, together they represent a major cause of morbidity and mortality related to sarcoidosis [1, 2]. Given the protean manifestations of sarcoidosis and potential involvement of any tissue, a comprehensive compilation of all reported rare manifestations of sarcoidosis is not possible in this monograph. Nonetheless, an approach to patients who may have rare manifestation of sarcoidosis can be constructed. These rare manifestations reflect the known pathophysiology and clinical behaviour of more common and easily recognisable systemic sarcoidosis. Alternative diagnoses must be excluded, particularly when there are deviations from well-established manifestations or an expected clinical course for sarcoidosis. Given their rarity, none of the clinical approaches or treatment recommendations for the conditions discussed below have been subjected to clinical trials, rigorous or otherwise. The author has seen patients with the conditions listed below, and offers an approach based on this experience and selected published literature. Emphasis will be placed on a systematic approach to these rare manifestations, focusing on organ systems that are not covered by other sections of this Monograph. General considerations An initial framework for approaching the challenge of diagnosing and treating rare manifestations of sarcoidosis can be formulated based on current knowledge of the disease and the expected clinical behaviour of sarcoidosis. In all cases, granulomatous inflammation from sarcoidosis interferes with local tissue homeostasis and function; thus, organ impairment is dependent on its location. When the clinician is confronted with identifying whether a rare manifestation of sarcoidosis is present in a patient with known sarcoidosis, an internet search of the medical literature is part of a recommended initial approach to establish a possible association. Invariably, the clinician must be prepared to consider competing diagnoses, particularly when a diagnosis of sarcoidosis has not been established. To confirm an association with sarcoidosis or an alternative diagnosis, directed diagnostic evaluations including biopsy, may be needed. In other situations, a trial of corticosteroid (CS) therapy may be indicated to assess whether there is a clinical response consistent with sarcoidosis. With rare manifestations of sarcoidosis, a leading concern is whether the specific clinical problem is the result of an alternative, nonsarcoidosis pathological process. The following generalisations on the clinical behaviour of sarcoidosis provide a useful