Subcutaneous Mycoses

Question 1

Subcutaneous Mycoses

Answer 1

Due to traumatic implantation (skin trauma)
Agents are ALL soil saprophytes
More significant

Question 2

Most Common Subcutaneous Infections

Answer 2

Sporotrichosis
Mycetoma
Chromomycosis

Question 3

Sporotrichosis

Answer 3

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

Question 4

Microscopic Characteristics of Sporothriz schencki

Answer 4

Conidiophores arise from thin septate hyphae TAPERED towards end, and
Conidia are formed in clusters with their arrangement to a FLOWER “DAISIES”.
CIGAR SHAPED

Question 5

A chronic suppurative infection of subcutaneous tissue and contagious bone

Answer 5

Mycetoma

Question 6

Most common Site of infection

Answer 6

FEET

Question 7

Mycetoma

Answer 7

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

Question 8

Hallmark of Mycetoma

Answer 8

Fluids Granules/Grains

Question 9

Microscopic Morphology: S. apoiospermum

Answer 9

Single celled, TRUNCATE BASES, simple or branched conidiophores, annelation - RING LIKE SCARS ON APEX

Question 10

Microscopic Morphology: S. prolificans

Answer 10

Basally swollen , FLASKED SHAPED ANNELIDES

Question 11

This organism is inhibited by cycloheximide

Answer 11

P. boydii

Question 12

True or False.
S. apiospermum - does not grow in cycloheximide
S. prolificans - grow with cycloheximide

Answer 12

False.
S. apiospermum - GROW in cycloheximide
S. prolificans - DOESN’T GROW with cycloheximide

Question 13

Microscopic appearance of P. boydii

Answer 13

Sepatated Hyphae are hyaline
Conidiophores with annelides
LARGE BROWN CLEISTIOTHECIA (sac-like structure with asci and ascospores)

Question 14

Mycetoma - Exophiala jeanselmei

Answer 14

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.

Question 15

Mycetoma - Madurella grisea

Answer 15

Macroscopic: Leathery folded with radial grooves and light brown greyish surface mycelium.

Microscopic:
Septate Hyphae - branched and dark
Grains: Black, deeply pigmented periphery

Question 16

Mycetoma - Medurella mycetomatis

Answer 16

Macroscopic - Brown diffusible pigment

Microscopic - Conidia; Flasked-shaped PHIALIDES (1st), Pyriform conidia wit truncated bases (2nd)

Question 17

Chromoblastomycosis

Answer 17

Agent: Chlodosporium, Phiolophora, Fonsecaea
Characteristic: Slowly progressive GRANULOMATOUS infection; “Wart-like lesions”
Colonial appearance: Darkly pigmented colonies, heaped-up, VELVETY appearance; Reverse - Jet black

Question 18

A slowly progressive GRANULOMATOUS lesions by dematiaceous fungi.

Answer 18

Chromomycosis/Chromoblastomycosis

Question 19

Three Types of Sporulation in Chromomycosis

Answer 19

Chladosporium Type - shield shape
Rhinocladiella Type - Single at tend and side of conidiophore
Phiolophora Type - Conidia extrude from flasked-shaped phialides

Question 20

Fonseceae spp. to cause Chromoblastomycosis

Answer 20

F. pedrosoi (most common)
F. monophora
F. compacta (morphological variant of F. pedrosoi)

Question 21

Fonseceae spp. Characteristics

Answer 21

Indistinct MELANISED conidiophores with BLUNT, SCATTERED DENTICLES
Pale olivaceous
Formation of Sclerotic Bodies

Question 22

Most common cause of Chromoblastomycosis

Answer 22

F. pedrosoi

Question 23

A specific structure formed by Fonseceae spp. in single or clustered, round, tick walled, dark brown to black organism that multiply by planate division

Answer 23

Sclerotic Bodies

Question 24

True or False.
F. Pedrosoi - Long Conidial chains with Short denticles. F. monophora are shorter conidial chains and denticles are slightly longer.

Answer 24

1st Statment: True

2ns Statement: False. F. monophora have slighlty longer chains with slightly shorter denticle

Question 25

Most common indoor and outdoor Molds

Answer 25

C. carrionii

Question 26

C. carrionii

Answer 26

Macroscopic: Olivaceous- black colony Microscopic: Branching olivaceous green, elongate conidiophores, smooth walled conidia; Bulboes phialides

Question 27

C. bandium

Answer 27

Macroscopic: Olivaceous grey colony, suede like Microscopic: Chains of undifferentiated conidiophores, Pale brown, Ellipsoid to Oblong-Ellipsoid

Question 28

Difference of C. bandium to C. carrionii

Answer 28

1. Absence of conidia with distinct pigmented Hila 2. No shield cell characteristic 3. Grows at 42C

Question 29

A NEUROTROPIC fungus involving CNS and associated with Keratitis, Otitis, Pneumonia, and Endocarditis.

Answer 29

Wingellia dermatitidis

Question 30

W. dermatitidis

Answer 30

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,

Question 31

P. verrucosa

Answer 31

Microscopic: FUNNEL/CUP SHAPED DARKLY PIGMENTED COLLARETTES Macroscopic: Dome Shaped,

Question 32

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.

Answer 32

A The dermatophytes are molds and are not thermally dimorphic.

Question 33

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.

Answer 33

C Sporothrix is often acquired by penetrating wounds sustained while gardening.

Question 34

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.

Answer 34

(B) A methenamine silver stain examined in the light microscope revealed budding yeasts.

Question 35

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

Answer 35

b. Sporotrichosis

Question 36

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

Answer 36

A. Dematiaceous mold