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Syn: South
American Blastomycosis.
Paracoccidioidomycosis is a progressive
pulmonary infection caused by the single dimorphic species
Paracoccidioides brasiliensis.
Geographic distribution:
The disease is highly
endemic in South America, particularly in Brazil, Colombia, and
Venezuela. Cases have also been reported from Central America and
Mexico, but cases discovered in the United States have all been
acquired within endemic areas of Latin America.
Clinical
presentation: Paracoccidioidomycosis is predominantly
a disease of rural adult males.
The primary focus of infection occurs
in the lungs, but pulmonary involvement may be overshadowed clinically
by manifestations of limited or widespread lymphatic and hematogenous
dissemination.
Paracoccidioidomycosis of childhood is
an acute progressive pulmonary infection that rapidly disseminates to
lymph nodes, liver and spleen.
In adults, the infections pursues a
more chronic course with variable periods of clinical latency.
Pathological
features:
Image1
;
Image2 ;
Image3
(Dr Tsutsumi )
Acute progressive pulmonary
paracoccidioidomycosis is an acute suppurative pneumonitis that
contains scattered multinucleated giant cells and yeast forms of P.
brasiliensis.
The chronic progressive form is
characterized by granulomatous inflammation with extensive
interstitial and conglomerate fibrosis, necrosis, and arterial intimal
fibrosis leading to cor pulmonale.
At autopsy, disseminated lesions are
found in extrathoracic sites in the majority of patients, chiefly
involving the oropharyngeal mucosa, larynx, trachea, skin, lymph
nodes, liver, spleen, adrenal glands, intestine, and kidneys.
The larynx is the third most
commonly involved organ in paracoccidioidomycosis .
These disseminated lesions are
granulomatous or suppurative and granulomatous.
Cutaneous and mucosal lesions also
exhibit pseudoepitheliomatous hyperplasia similar to that typically
found in the lesions of
blastomycosis
and sporotrichosis. Visit:
Coccidioidomycosis
;
Histoplasmosis
.
In tissue sections, P. brasiliensis
occurs predominantly as pleomorphic yeast-like cells, 5 to 60
micrometer in diameter, that reproduce by budding.
Small yeast forms and hyphae are
occasionally found.
Thick-walled, “mosaic” cells with
fractured walls are often numerous in chronic pulmonary lesions.
A definitive histopathologic diagnosis
of paracoccodioidomycosis requires identification of characteristic
multiple-budding cells that resemble a ship’s steering wheel.
The blastoconidia produced by these
cells have an oval, tubular, or tear-drop configuration and are
attached to parent cells by narrow necks.
Diagnosis:
The
precise diagnosis of paracoccidioidomycosis, in most cases, is
established by direct methods and indirect immunological tests.
The latter method is reliant on the identification of the
host's humoral responses, which are usually impaired or
absent in patients with severe juvenile forms of the
disease and in immunocompromised patients.
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