SplendoreHoeppli

Splendore-Hoeppli phenomenon is a histopathological finding in which intensely eosinophilic, amorphous material surrounds a pathogen or foreign material in tissue, often forming asteroid-like radiations around the organism. The appearance is best appreciated on light microscopy with routine stains and is a descriptive clue rather than a diagnosis in itself.

The eosinophilic material is thought to reflect deposition of immune complexes and fibrin, with debris from inflammatory cells, in response to antigenic material from the organism or foreign body. Eosinophils and other inflammatory cells are typically present in the surrounding tissue, contributing to the characteristic appearance of the deposit.

The phenomenon is not pathogen-specific and has been described in a variety of infectious contexts. It is classically reported in fungal infections such as sporotrichosis and phaeohyphomycosis, but associations include bacterial infections such as Actinomyces and Nocardia (including botryomycosis), parasitic infections, and occasionally noninfectious contexts where antigen-antibody reactions occur.

Significance and interpretation: Splendore-Hoeppli is a useful histopathologic clue that supports a local immune reaction to an infectious agent or foreign material, but it does not identify a single organism. Its recognition can guide ancillary testing, including special stains and microbiologic culture, to determine the causative pathogen.

History: the phenomenon is named for Augusto Splendore and Anton Hoeppli, who described the finding in the late 19th and early 20th centuries. It remains a descriptive feature in pathology and microbiology, illustrating the host’s immune response at sites of infection.