Page 197 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 6-22 Infectious Diseases

PARACOCCIDIOIDOMYCOSIS

Paracoccidioidomycosis, also known as South American
blastomycosis, is a disease that is seen almost exclusively
in regions of Central and South America. It is caused
by the dimorphic fungus, Paracoccidioides brasiliensis.
Most infections are acquired by direct inhalation of the Plaques on lips,
chlamydospores. The fungus is found in the environ- nose, and tongue
ment in the mycelial or mold phase; it converts to the with cervical
yeast phase at body temperature. Brazil has the highest lymphadenopathy
incidence of paracoccidioidomycosis. Primary lung
infection may lead to disseminated disease, with the
skin being secondarily infected. Direct inoculation into
the skin causes primary cutaneous disease.
Clinical Findings: This fungal infection is more
common in men than in women, for reasons poorly Bilateral pulmonary infiltrates, which
understood. It may be that men are more likely to have closely resemble tuberculosis. Pulmonary
occupational exposures (most commonly, farming). A lesions may range from minimal to very
protective effect of estrogen also has been hypothe- extensive.
sized. There is no race predilection. Immunocompetent
hosts who are exposed to the fungus are likely to
develop a subclinical infection. Then, either the fungus
becomes walled off in the form of granulomas within
the lung or the patient goes on to develop clinical
disease. Serological testing may show evidence of past
exposure in healthy subjects with no clinical findings.
Some hosts have a constellation of flu-like symptoms
that include malaise, weight loss, fatigue, fever, pneu-
monitis, and pleurisy. Progressive pulmonary lesions with
E. Hatton
may occur regardless of immune status, but they are
more severe in patients who are immunosuppressed.
Bilateral pulmonary infiltrates are seen on chest radi- Several double-contoured yeast-phase
ography and are similar to the radiographic findings of Yeast phase of P. brasiliensis in fresh cells with single buds in a giant cell
unstained sputum prepared with 10%
tuberculosis. The infiltrates often form consolidated NaOH, showing double walls with from a skin lesion
areas with cavitations that heal with emphysematous single and multiple budding
changes. Almost all cases of paracoccidioidomycosis
affect the lung. Once established, the fungus is able to
disseminate to the skin, draining lymph nodes, adrenal
glands, central nervous system, peritoneum, and gastro-
intestinal tract.
Skin lesions in paracoccidioidomycosis come in two
distinct varieties. Disseminated disease is the more fre- 6
quently encountered subtype. The lesions are predomi- 5 1
nantly on the head and neck, especially around the oral
and nasal passages. The oral mucosal membranes and
tongue are involved. Nasal and pharyngeal ulcerations
are so frequently encountered that they have been given 4 2
a name, Aguiar-Pupo stomatitis. The mucosal lesions are 3
often peppered with pinpoint hemorrhagic areas. The
skin findings may include papules, nodules, or fungat-
ing plaques. Ulceration is almost universal, and patients Precipitin test. Antigen in central Mycelial colonies of
complain of pain and swelling. Cervical lymph nodes well; serum from five different P. brasiliensis grown on Colonies of yeast form
are enlarged. The infected lymph nodes often form patients in peripheral wells Sabouraud’s medium at room of P. brasiliensis grown
sinus tracts to the skin and drain spontaneously. showing precipitin bands. Wells temperature. Downy appearance on blood agar at 37 C
The second form of cutaneous paracoccidioidomyco- 4 and 5 are from the same patient is caused by filamentous hyphae
sis is caused by direct inoculation of the fungus. The before and after treatment, with intercalate or terminal
fungal elements are normally found in the soil, and evidencing response. chlamydospores.
piercing of the skin with a contaminated object can lead
to primary cutaneous paracoccidioidomycosis. These
lesions appear as papules or draining tender nodules seen in the shape of a “mariner’s wheel,” which is highly The host response to this fungus depends on an intact
with or without overlying ulceration. Some may spon- characteristic and specific for P. brasiliensis. The fungus Th1 helper T-cell response.
taneously resolve, but most slowly enlarge. can be highlighted with a multitude of special staining Treatment: Treatment with itraconazole has had
Histology: Skin biopsy specimens show pseudocarci- methods, including periodic acid–Schiff and sliver great success and has drastically altered the prognosis
nomatous hyperplasia of the epidermis with varying stains. The fungus is easily cultured on Sabouraud’s of this disease. As with all systemic fungal infections,
degrees of ulceration and abscess formation. There is a medium and shows fluffy white colonies. treatment courses last for months to a year. Historically,
mixed inflammatory infiltrate. Suppurative granuloma- Pathogenesis: The fungus P. brasiliensis has unusual sulfonamides were used. If left untreated, this disease has
tous inflammation is seen within the underlying dermis. living requirements, and its growth in the environment a significant mortality rate. Ketoconazole and flucon-
The fungus can be seen on routine hematoxylin and is dependent on the soil pH, the altitude, and a consis- azole have also been used successfully, and amphotericin
eosin staining with close inspection. The cells of the tent temperature. Alterations in the optimal growing B is now reserved for the most severe cases and for those
yeast phase are thick walled and refractile. They can be conditions decrease the survivability of the organism. that fail to respond to azole or sulfonamide therapy.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 183