A 49 year old female with shoness of breath is found to have hilar lymphadenopathy on chest x-ray. Biopsy of one of the lymph nodes reveals granulomas, and is highly suggestive of sarcoidosis. Which of the following histological findings must have been present in the biopsy material to suppo the diagnosis of granulomatous inflammation?
A granuloma is defined as a focus of chronic inflammatory reaction in which the predominant cell type is the epithelioid macrophage or histiocyte. Epithelioid histiocytes are recognized on standard H&E preparation by their pale pink cytoplasm and indistinct cell boundaries. Granulomas are generally surrounded by a ring of lymphocytes and infrequent plasma cells. The granulomas of sarcoidosis usually contain many multinucleated giant cells, and frequently these giant cells contain stellate inclusions called asteroid bodies Caseous necrosis describes the gross appearance of cheesy, necrotic debris filling a nodule of active tuberculosis, but also has come to describe its characteristic amorphous and eosinophilic appearance on H&E sections. Caseous necrosis is suggestive of tuberculosis, not sarcoidosis. Over time, fibroblasts proliferate within the core of old, inactive granulomas, eradicating the histiocytes and stereotypical appearance and producing a dense collagenous scar.
Asteroid bodies
Caseous necrosis
Epithelioid histiocytes
Fibroblast proliferation