Cryptococcal yeast cells on a sputum smear

Abstract

Sputum cytology may play an important role in the detection of uncommon micro-organisms, especially in patients with HIV infection. Cryptococcosis is a systemic mycosis whose principal causal agent is Cryptococcus neoformans (CN), a yeastshaped encapsulated fungus that reproduces by budding. Its development almost always involves a state of immunodeficiency (AIDS, neoplasia, corticotherapy, etc). The organs most frequently affected are the lungs and the meninges. Other sites affected are the skin, liver, bones, etc. Here, the presence of cryptococcal yeast cells on a sputum smear from spontaneous expectoration, and stained with the Papanicolaou method, is shown. The patient, a 43 years old male HIV(+), also had meningeal and cutaneous lesions. A chest X-ray showed bilateral nodular infiltrates. The structures observed (Figs. C-1A and B) are pinkcolored, round in shape, and vary in size between 3 and 12 microns. Some are surrounded by a clear halo corresponding to the capsule of the yeast. Histochemical staining techniques utilized such as Grocott and PAS shown yeasts with budding phenomena. Because the capsule is composed of polysaccharides, mucicarmin staining is more specific. By means of negative staining with Indian ink, the whole preparation is stained except for the capsule. Other diagnostic procedures, such as culture of secretions and serologic test, are more sensitive but timeconsuming and are more expensive. CN is a fungus that is ubiquitous in the ground (it is abundantly present in bird droppings, particularly those of