Laryngeal Histoplamosis Overview

Omar Ramadan*

Laryngeal Histoplamosis Overview.

The fungus usually exists in the mycelial phase at room temperature. However once the spores are inhaled, the spores
transform to the yeast phase which is responsible for the human infection and which leads to pulmonary infection that may be
complicated by haematogenous spread to other organs.

The clinical scenario of ranges from a mild infection localized to the gastrointestinal tract, skin, larynx or other extra pulmonary sites to severe disseminated multisystem disease that involve the bone marrow, liver, spleen and lungs.

The most common clinical presentation of laryngeal histoplasmosis is secondary to chronic disseminated
histoplasmosis as a result of haematogenous spread. There are a few reports of sporadic primary laryngeal histoplasmosis cases.

The degree of infection is determined by the size of the inoculum and prior immune status of the host. It is often
associated with general symptoms such low grade fever, weight loss and fatigue. Other symptoms of laryngeal histoplasmosis may
include hoarseness, dysphagia, sore throat, cough and occasionally stridor.

In the biopsy, it can be observed with hematoxylin-eosin granulomatous tissue, necrosis, and infiltration of giant cells,
lymphocytes, plasma cells and many macrophages. By using special stains such as coloring Gomorimethenamine-silver, coloring periodic acid-schiff staining or Gridley technique40
to identify macrophages and these cell containing hyphae.

Macroscopically, histoplasmosisshouldbe differentiated from syphilis, tuberculosis, carcinoma, mid-line granuloma,
mucormycosis, lymphoma, and other granulomatous diseases. Anti-histoplasma serological tests using complement
fixation and immune-diffusion methods are positive in about
90% of immune-competent patients and 70% of immunecompromised patients. Antibody tests may be false negative in
immune-compromised patients. The antibodies usually start to
appear during the second month after exposure in acute phase,
and they may remain positive for several years.

Otolaryngol Open J. 2016; 2(5): 141-149. doi: 10.17140/OTLOJ-2-130