Subcutaneous Mycoses Flashcards
Subcutaneous Mycoses
Due to traumatic implantation (skin trauma)
Agents are ALL soil saprophytes
More significant
Most Common Subcutaneous Infections
Sporotrichosis
Mycetoma
Chromomycosis
Sporotrichosis
Agent: Sporothrix Schenckii
Growth sources: Roses and Sphagnum Moss
Manifestations:
Cutaneous - small local papules (arms/legs)
Lymphocutaneous - nodules in lymphatics are enlarged and discolored (buboes)
Bronchitis, TB -like - rare cases
Osteoarticular - most common extracutaneous disorder
Dioagnosis: Sporotrochin Skin Test
Microscopic Characteristics of Sporothriz schencki
Conidiophores arise from thin septate hyphae TAPERED towards end, and
Conidia are formed in clusters with their arrangement to a FLOWER “DAISIES”.
CIGAR SHAPED
A chronic suppurative infection of subcutaneous tissue and contagious bone
Mycetoma
Most common Site of infection
FEET
Mycetoma
Other name: Maduromycosis/Madura Foot Infection
Agents:
Sexual Form - P. boydii
Asexual Form - S. apiospermum & S. prolificans
E. jeanselmei, M. grisea, M. mycetomatis
Manifestation:
Discharge of viscous purulent fluid/serosanguinous fluid with GRANULES
Spread to bones, causing deformity
Hallmark of Mycetoma
Fluids Granules/Grains
Microscopic Morphology: S. apoiospermum
Single celled, TRUNCATE BASES, simple or branched conidiophores, annelation - RING LIKE SCARS ON APEX
Microscopic Morphology: S. prolificans
Basally swollen , FLASKED SHAPED ANNELIDES
This organism is inhibited by cycloheximide
P. boydii
True or False.
S. apiospermum - does not grow in cycloheximide
S. prolificans - grow with cycloheximide
False.
S. apiospermum - GROW in cycloheximide
S. prolificans - DOESN’T GROW with cycloheximide
Microscopic appearance of P. boydii
Sepatated Hyphae are hyaline
Conidiophores with annelides
LARGE BROWN CLEISTIOTHECIA (sac-like structure with asci and ascospores)
Mycetoma - Exophiala jeanselmei
Macroscopic: Greenish gray to black, mucoid, smooth with tufts of aerial mycelium and becoming sude-like texture.
Microscopic: Bradly ellipsoidal cells, inflated, smooth thin walled with inconspicuous basal scars.
Mycetoma - Madurella grisea
Macroscopic: Leathery folded with radial grooves and light brown greyish surface mycelium.
Microscopic:
Septate Hyphae - branched and dark
Grains: Black, deeply pigmented periphery
Mycetoma - Medurella mycetomatis
Macroscopic - Brown diffusible pigment
Microscopic - Conidia; Flasked-shaped PHIALIDES (1st), Pyriform conidia wit truncated bases (2nd)
Chromoblastomycosis
Agent: Chlodosporium, Phiolophora, Fonsecaea
Characteristic: Slowly progressive GRANULOMATOUS infection; “Wart-like lesions”
Colonial appearance: Darkly pigmented colonies, heaped-up, VELVETY appearance; Reverse - Jet black
A slowly progressive GRANULOMATOUS lesions by dematiaceous fungi.
Chromomycosis/Chromoblastomycosis
Three Types of Sporulation in Chromomycosis
Chladosporium Type - shield shape
Rhinocladiella Type - Single at tend and side of conidiophore
Phiolophora Type - Conidia extrude from flasked-shaped phialides
Fonseceae spp. to cause Chromoblastomycosis
F. pedrosoi (most common)
F. monophora
F. compacta (morphological variant of F. pedrosoi)
Fonseceae spp. Characteristics
Indistinct MELANISED conidiophores with BLUNT, SCATTERED DENTICLES
Pale olivaceous
Formation of Sclerotic Bodies
Most common cause of Chromoblastomycosis
F. pedrosoi
A specific structure formed by Fonseceae spp. in single or clustered, round, tick walled, dark brown to black organism that multiply by planate division
Sclerotic Bodies
True or False.
F. Pedrosoi - Long Conidial chains with Short denticles. F. monophora are shorter conidial chains and denticles are slightly longer.
1st Statment: True
2ns Statement: False. F. monophora have slighlty longer chains with slightly shorter denticle
Most common indoor and outdoor Molds
C. carrionii
C. carrionii
Macroscopic: Olivaceous- black colony
Microscopic: Branching olivaceous green, elongate conidiophores, smooth walled conidia; Bulboes phialides
C. bandium
Macroscopic: Olivaceous grey colony, suede like
Microscopic: Chains of undifferentiated conidiophores, Pale brown, Ellipsoid to Oblong-Ellipsoid
Difference of C. bandium to C. carrionii
- Absence of conidia with distinct pigmented Hila
- No shield cell characteristic
- Grows at 42C
A NEUROTROPIC fungus involving CNS and associated with Keratitis, Otitis, Pneumonia, and Endocarditis.
Wingellia dermatitidis
W. dermatitidis
Macroscopic:
Black to Olive black
Budding yeasts and Hyphae
Moist, Shiny, Velvety at Periphery
Microscopic: FLASK SHAPED TO CYLINDRICAL W/O COLLARETES
Septate Brown hyphae
Yeast cells are present
Brown Phialides, branched,
P. verrucosa
Microscopic: FUNNEL/CUP SHAPED DARKLY PIGMENTED COLLARETTES
Macroscopic: Dome Shaped,
Regarding ringworm and the dermatophytes, which one of the following is most
accurate?
(A) The dermatophytes are molds and are not thermally dimorphic.
(B) The drug of choice for the treatment of ringworm lesions is amphotericin B.
(C) The purpose of the KOH prep is to observe fungal antigens within infected cells.
(D) The dermatophytid reaction refers to the necrotic area typically seen in the center of ringworm lesions.
(E) The principal reservoir of dermatophytes in the genus Trichophyton is domestic animals such as dogs and cats.
A The dermatophytes are molds and are not thermally dimorphic.
Regarding sporotrichosis and Sporothrix schenckii, which one of the following is most accurate?
(A) The main reservoir of Sporothrix is dog feces.
(B) Laboratory diagnosis involves seeing a nonseptate mold in an aspirate of the lesion.
(C) Sporothrix is often acquired by penetrating wounds sustained while gardening.
(D) The treatment of choice for sporotrichosis is surgical removal of the lesion because there is no effective drug.
(E) Disease occurs primarily in patients who are deficient in the late-acting
complement components.
C Sporothrix is often acquired by penetrating wounds sustained while gardening.
Your patient is a 65-year-old woman with a 2-cm ulcerated lesion on the palm of her hand that has been gradually getting bigger during the past month. The lesion is only slightly tender and is not red, hot, or painful. A careful history reveals that
she was making holly wreaths for use at Christmas. (Holly leaves have sharp points.) She is afebrile and otherwise well. An aspirate of the lesion was
obtained. Which one of the following would best support a diagnosis of sporotrichosis?
(A) A culture on blood agar at 25°C revealed white, beta-hemolytic colonies.
(B) A methenamine silver stain examined in the light microscope revealed budding yeasts.
(C) A KOH preparation examined in the light microscope revealed septate
hyphae.
(D) A culture on Sabouraud’s agar at 37°C revealed a brownish mycelium with
green spores.
(E) An unstained sample examined in the dark field microscope revealed nonseptate hyphae.
(B) A methenamine silver stain examined in the light microscope revealed budding yeasts.
A landscaper noticed a hard, unmovable lump under
the skin of his index finger but decided to ignore it. A
month later, the lump ulcerated to present a necrotic
appearance, and two more lesions developed further
up the wrist and forearm. A histologic stain of material from deep in the lesions showed elongated yeast
cells resembling cigars. What disease is suspected?
a. Mycetoma
b. Sporotrichosis
c. Chromoblastomycosis
d. Blastomycosis
b. Sporotrichosis
A mold that produces colonies with a dark brown,
green-black, or black appearance of both the
surface and reverse side is classified as a:
A. Dematiaceous mold
B. Dermatophyte
C. Hyaline mold
D. Dimorphic fungus
A. Dematiaceous mold
