ABSTRACT
Sarcoidosis is an enigmatic systemic condition with a world-
wide distribution. The etiology remains unknown and treat-
ment remains empirical. The histological hallmark of the
‘sarcoid granuloma’ has led to the concept that a number of
diseases with a granulomatous component to their histo-
pathology may have a common or linked pathogenesis. Other
conditions that may co-exist may share a common genetic
milieu and/or similar immune-pathogenetic pathways. Differ-
ent disorders demonstrating non-caseating granulomas as part
of their pathology has led to many reports consisting of either
small case series or case reports purporting a linkage between
them and sarcoidosis. This concept has been challenged
by a recent large-scale epidemiological study that provides
a reassessment of sarcoid-associated diseases. This chapter
reviews the old and new associations. However, until the
etiologies of sarcoid are elucidated, the validity of even this
approach will remain observational. It does minimize the risk
of unwarranted associations being investigated.
