Subcutaneous Mycoses — MCQs
A patient with AIDS presents with meningitis. India ink staining shows encapsulated yeasts. Which organism is most likely?
Which of the following is most likely to be acquired by traumatic inoculation?
A patient from Himachal Pradesh gets a thorn prick and subsequently presents with a verrucous lesion on feet which on microscopy revealed "Copper penny bodies". The diagnosis is
Fungal infection which is acquired by traumatic inoculation is?
A forest worker developed skin lesions over the forearm, which initially started as macules but then became nodules. Histology of the nodule shows the following findings. Which of the following is true regarding this condition?
A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?
A farmer has an ulcer on leg with indurated margin and multiple sinuses with discharging granules. The likely diagnosis is -
Rhinosporidium seeberi is classified as a?
A patient presents with sinus tracts on the foot, and a smear reveals filamentous organisms.
A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?
Subcutaneous Mycoses Indian Medical PG Practice Questions and MCQs
Question 1: A patient with AIDS presents with meningitis. India ink staining shows encapsulated yeasts. Which organism is most likely?
- A. Candida albicans
- B. Cryptococcus neoformans (Correct Answer)
- C. Histoplasma capsulatum
- D. Coccidioides immitis
Explanation: ***Cryptococcus neoformans*** - This fungus is a common cause of **meningitis in AIDS patients** and characteristically appears as **encapsulated yeasts** on India ink staining of CSF. - The capsule excludes the ink, creating a distinct **halo** around the yeast cell, which is diagnostic. *Candida albicans* - While *Candida* can cause systemic infections, including meningitis, it typically presents as **pseudohyphae** or budding yeast without an obvious capsule on India ink stain. - *Candida meningitis* is less common in AIDS patients compared to *Cryptococcus*. *Histoplasma capsulatum* - This is a dimorphic fungus that causes **histoplasmosis**, often disseminated in AIDS patients, but typically manifests as **pulmonary disease** or hepatosplenomegaly. - It appears as small, **intracellular yeasts** within macrophages and would not show an encapsulated form on India ink stain in CSF. *Coccidioides immitis* - This dimorphic fungus causes **coccidioidomycosis**, which can lead to meningitis, particularly in immunocompromised individuals. - In CSF, it is seen as **spherules containing endospores**, not encapsulated yeasts, which is a distinct morphological feature.
Question 2: Which of the following is most likely to be acquired by traumatic inoculation?
- A. Coccidioides immitis
- B. Sporothrix schenckii (Correct Answer)
- C. Histoplasma capsulatum
- D. Aspergillus fumigatus
Explanation: ***Sporothrix schenckii*** - **Sporothrix schenckii** causes **sporotrichosis** (rose gardener's disease), which is classically acquired through **traumatic inoculation** via thorns, splinters, or plant material contaminated with the fungus. - This dimorphic fungus exists in soil and vegetation, and the mode of transmission is characteristically associated with **gardeners, farmers, and florists** who experience penetrating injuries during their work. - Presents as lymphocutaneous infection with nodular lesions along lymphatic channels. *Histoplasma capsulatum* - Causes histoplasmosis and is endemic to certain regions (Ohio and Mississippi River valleys). - Primarily acquired through **inhalation of microconidia** from soil contaminated with bird or bat droppings, not through traumatic inoculation. - Presents as pulmonary infection in most cases. *Coccidioides immitis* - Causes coccidioidomycosis (Valley Fever) and is found in arid regions of southwestern United States. - Acquired through **inhalation of airborne arthroconidia** from disturbed soil, not through traumatic inoculation. - While rare cases of primary cutaneous infection can occur, inhalation remains the typical route. *Aspergillus fumigatus* - Ubiquitous environmental mold associated with decaying organic matter. - Primarily causes disease through **inhalation of conidia**, leading to allergic reactions, aspergilloma, or invasive aspergillosis in immunocompromised patients. - Not typically associated with traumatic inoculation as the primary mode of infection.
Question 3: A patient from Himachal Pradesh gets a thorn prick and subsequently presents with a verrucous lesion on feet which on microscopy revealed "Copper penny bodies". The diagnosis is
- A. Sporothrix
- B. Chromoblastomycosis (Correct Answer)
- C. Verruca vulgaris
- D. Eumycetoma
Explanation: ***Chromoblastomycosis*** - The presence of **"copper penny bodies" (sclerotic bodies or Medlar bodies)** on microscopy is pathognomonic for chromoblastomycosis. - This chronic fungal infection typically presents as **verrucous lesions** on the skin, often in exposed areas like the feet, following **traumatic inoculation**, such as a thorn prick. *Eumycetoma* - Characterized by the formation of **grains or granules** composed of fungal hyphae within subcutaneous tissue, usually with **multiple draining sinuses**. - While it can be caused by a thorn prick and affect the feet, it does not typically show "copper penny bodies" on microscopy. *Sporothrix* - Causes **sporotrichosis**, which often presents as **lymphocutaneous nodules** that ulcerate and follow lymphatic drainage, or fixed cutaneous lesions. - Microscopic examination typically reveals **cigar-shaped budding yeasts** in tissue, not copper penny bodies. *Verruca vulgaris* - This is a common **viral wart** caused by the **Human Papillomavirus (HPV)**, presenting as a raised, rough, cauliflower-like papule [1]. - Histologically, it shows **koilocytes** (HPV-infected keratinocytes), but no fungal elements like "copper penny bodies." [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, p. 1178.
Question 4: Fungal infection which is acquired by traumatic inoculation is?
- A. Sporothrix (Correct Answer)
- B. Coccidioides
- C. Paracoccidioides
- D. Blastomyces
Explanation: ***Sporothrix*** - **Sporotrichosis** is characteristically acquired through **traumatic inoculation** of the fungus, often from contact with soil, thorns, or decaying vegetation. - The organism causes **cutaneous lymphatic disease**, presenting as nodular lesions along lymphatic drainage paths. *Blastomyces* - **Blastomycosis** is typically acquired by inhaling airborne fungal spores, usually from **soil rich in organic matter** or decaying wood. - It primarily affects the **lungs** and can disseminate to the skin, bones, and other organs, but is not primarily associated with traumatic inoculation. *Coccidioides* - **Coccidioidomycosis** (Valley Fever) is acquired by inhaling **arthroconidia** present in dust or soil in endemic areas. - It is a **pulmonary infection** that can disseminate to other body sites, and its entry is almost exclusively respiratory, not traumatic. *Paracoccidioides* - **Paracoccidioidomycosis** is acquired by inhaling airborne fungal propagules, typically found in **soil in Latin America**. - It primarily causes **chronic pulmonary disease** and can spread to mucous membranes, skin, and lymph nodes, with no known association with traumatic inoculation.
Question 5: A forest worker developed skin lesions over the forearm, which initially started as macules but then became nodules. Histology of the nodule shows the following findings. Which of the following is true regarding this condition?
- A. Angioinvasion is common especially in people with hemolytic anemia
- B. These bodies are formed by engulfment of the dead fungi by the macrophages
- C. It is a dematiaceous fungus (Correct Answer)
- D. Infection commonly spreads to involve tendon, muscle and bone
Explanation: The image displays **chromoblastomycosis**, a fungal infection characterized by **medlar bodies** or **sclerotic bodies**. These are thick-walled, septate, dematiaceous (pigmented) fungal cells that resemble copper pennies. The patient's history of being a forest worker with skin lesions progressing from macules to nodules is consistent with this diagnosis as it's often associated with **traumatic inoculation** from contaminated plant material. ***It is a dematiaceous fungus*** - The image shows **"copper pennies"** or **sclerotic bodies**, which are characteristic of dematiaceous (pigmented) fungi causing chromoblastomycosis. - These fungi contain **melanin** in their cell walls, which contributes to their characteristic dark appearance. - Common causative agents include *Fonsecaea pedrosoi*, *Phialophora verrucosa*, and *Cladophialophora carrionii*. *Angioinvasion is common especially in people with hemolytic anemia* - **Angioinvasion** is not a feature of chromoblastomycosis, which typically remains confined to the **skin and subcutaneous tissue**. - Angioinvasion is characteristic of **mucormycosis** and **aspergillosis**, particularly in immunocompromised patients, not chromoblastomycosis. *These bodies are formed by engulfment of the dead fungi by the macrophages* - The **sclerotic bodies** are **living fungal cells** in their tissue-specific form, not dead fungi engulfed by macrophages. - They are a distinct morphological form of the fungus, adapting to growth within the host tissue, and are **actively pathogenic**. - These thick-walled structures allow the fungus to persist in tissue and resist host defenses. *Infection commonly spreads to involve tendon, muscle and bone* - Chromoblastomycosis causes **chronic, localized infections** primarily of the **skin and subcutaneous tissue**. - While local tissue destruction can occur, **deep invasion** into tendons, muscles, or bones is **rare** and occurs only in severe, long-standing cases. - The infection typically remains confined to cutaneous and subcutaneous layers without dissemination.
Question 6: A plant prick can produce sporotrichosis. Which of the following statements about sporotrichosis is false?
- A. Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding
- B. Most cases are acquired via cutaneous inoculation
- C. It is an occupational disease of butchers, doctors (Correct Answer)
- D. Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics
Explanation: ***It is an occupational disease of butchers, doctors*** - Sporotrichosis is an **occupational hazard for gardeners, florists, and agricultural workers** due to exposure to decaying plant matter, not typically for butchers or doctors. - The disease is caused by **direct inoculation** of the fungus *Sporothrix schenckii* into the skin, often through a thorn prick or minor trauma. *Most cases are acquired via cutaneous inoculation* - This statement is **true** as sporotrichosis is primarily caused by **traumatic implantation** of fungal spores into the skin. - Common sources include **thorns, splinters, sphagnum moss**, and other plant materials. *Enlarged lymph nodes extending centripetally as a beaded chain are a characteristic finding* - This statement is **true** and describes the classic **lymphocutaneous sporotrichosis**, where lesions and **nodular lymphangitis** track along lymphatic channels. - The "beaded chain" appearance refers to the multiple subcutaneous nodules formed along the lymphatic vessels. *Is a chronic mycotic disease that typically involves skin, subcutaneous tissue and regional lymphatics* - This statement is **true** because sporotrichosis is a **slow-progressing fungal infection** that primarily affects the skin, the tissue just beneath the skin, and the lymphatics draining the infected area. - While systemic dissemination can occur in immunocompromised individuals, the **cutaneous and lymphocutaneous forms** are most common.
Question 7: A farmer has an ulcer on leg with indurated margin and multiple sinuses with discharging granules. The likely diagnosis is -
- A. Lupus vulgaris
- B. Actinomycosis
- C. Scrofuloderma
- D. Mycetoma (Correct Answer)
Explanation: ***Mycetoma*** - This is the **correct diagnosis** characterized by the classic triad: **tumefaction** (swelling with indurated margin), multiple **draining sinuses**, and discharge of **granules**. - The **occupational history** (farmer with soil exposure) and **location on the leg** are highly suggestive of mycetoma, particularly common in agricultural workers. - The granules are **colonies of microorganisms** (either fungi [eumycetoma] or bacteria [actinomycetoma]) aggregated and encased in a cement-like matrix, a distinctive feature of this chronic infection. - **Key distinguisher**: Mycetoma has a predilection for the **lower extremities**, especially the foot and leg, in individuals with occupational soil exposure. *Actinomycosis* - Actinomycosis is a bacterial infection caused by *Actinomyces* species, which also forms abscesses and draining sinuses with characteristic **"sulfur granules."** - **Why incorrect**: While actinomycosis shares features of sinuses and granules, it most commonly affects the **cervicofacial (50-60%)**, **thoracic**, or **abdominal** regions. - **Leg involvement is rare** for actinomycosis, making mycetoma the more likely diagnosis in this clinical scenario. - The occupational history and typical location favor mycetoma over actinomycosis. *Lupus vulgaris* - This is a form of **cutaneous tuberculosis** presenting as red-brown plaques or nodules, often with an **"apple-jelly" appearance** on diascopy. - While it can cause ulcers, it typically does **not present with deep-seated sinuses and discharging granules**, which are pathognomonic for mycetoma. *Scrofuloderma* - This is a form of cutaneous tuberculosis that develops from the direct extension of underlying **tuberculous adenitis** or **osteomyelitis** to the skin. - It presents as cold abscesses that eventually rupture, forming irregular ulcers and sinuses, but typically **lacks the distinct discharging granules** of mycetoma. - The clinical presentation with granular discharge clearly differentiates mycetoma from scrofuloderma.
Question 8: Rhinosporidium seeberi is classified as a?
- A. Bacteria
- B. Mesomycetozoa (Correct Answer)
- C. Fungi
- D. Protozoa
Explanation: ***Mesomycetozoa*** - *Rhinosporidium seeberi* belongs to the **Mesomycetozoa** clade, formerly known as Ichthyosporea or DRIPs (Dermocystidium, Rosette agent, Ichthyophonus, Psorospermium). - This classification is based on **molecular phylogenetic analysis** which shows it as an aquatic obligate parasite, distinct from true fungi and protozoa. *Fungi* - While *Rhinosporidium seeberi* was historically and morphologically mistaken for a fungus, genetic analysis has revealed it is **not a true fungus**. - Its **cell wall composition** and **reproductive structures** differ significantly from those of true fungi. *Bacteria* - Bacteria are **prokaryotic organisms** lacking a membrane-bound nucleus and other organelles, which is fundamentally different from the eukaryotic structure of *Rhinosporidium seeberi*. - *Rhinosporidium seeberi* exhibits complex life cycles and **spore formation**, a characteristic not found in bacteria. *Protozoa* - Protozoa are typically **unicellular eukaryotic organisms** that are often motile and generally reproduce by fission. - *Rhinosporidium seeberi* has a more complex **multicellular developmental cycle** and growth form that distinguishes it from typical protozoa.
Question 9: A patient presents with sinus tracts on the foot, and a smear reveals filamentous organisms.
- A. Sporothrix
- B. Nocardia (Correct Answer)
- C. Dermatophytes
- D. Candida
Explanation: ***Correct: Nocardia*** - **Nocardia species** cause **actinomycetoma**, a chronic infection characterized by **sinus tracts** discharging purulent material with sulfur granules - Smear shows **branching filamentous organisms** that are gram-positive and partially acid-fast - Classic presentation: sinus tracts on foot with filamentous organisms on direct microscopy - Key features: aerobic actinomycetes, branching at acute angles (45°) *Incorrect: Sporothrix* - Causes **sporotrichosis** (lymphocutaneous nodules along lymphatics), not sinus tracts - **Dimorphic fungus** diagnosed primarily by culture, not direct smear - Clinical presentation: nodular lesions following trauma (rose gardener's disease) - Does not show filamentous organisms on direct smear *Incorrect: Dermatophytes* - Cause **superficial infections** of skin, hair, and nails (tinea pedis, ringworm) - Do not form **deep sinus tracts** or involve subcutaneous tissue - Microscopy shows septate hyphae in skin scrapings, not in discharge from sinus tracts - Clinical presentation completely different from actinomycetoma *Incorrect: Candida* - **Yeast** causing mucocutaneous infections (thrush, vaginitis) or systemic candidiasis - Does not cause **sinus tracts** on the foot - Microscopy reveals **budding yeasts and pseudohyphae**, not true branching filaments - Not associated with actinomycetoma-type presentations
Question 10: A 56 year old gardener presents with an ulcerative nodule with purulent discharge on his right index finger. He had a prick with a thorn, at the same site around a month back. Which one of the following infections is most likely?
- A. Chromoblastomycosis
- B. Phaeohyphomycosis
- C. Mycetoma
- D. Sporotrichosis (Correct Answer)
Explanation: ***Sporotrichosis*** - This presentation, an **ulcerative nodule with purulent discharge** on a finger after a **thorn prick** in a gardener, is classic for **sporotrichosis** (rose gardener's disease). - The organism, *Sporothrix schenckii*, is found in soil, plants, and decaying vegetation and typically enters through **skin trauma**. *Chromoblastomycosis* - Characteristically presents with **verrucous (warty) plaques or nodules** that slowly enlarge; it does not typically show the ulcerative nodule with purulent discharge found here. - While it can be acquired through trauma, the **morphology of the lesions** differs from the described case. *Phaeohyphomycosis* - This is a broad term for infections caused by dematiaceous (pigmented) fungi that typically present as **subcutaneous cysts, abscesses, or nodules**, but the specific clinical picture of **lymphocutaneous spread** following trauma is less characteristic than sporotrichosis. - The lesions tend to be more **encapsulated or abscess-like** rather than the ulcerative, purulent nodule described. *Mycetoma* - Mycetoma presents as a **chronic, localized, progressively destructive infection** of the skin, subcutaneous tissue, fascia, and bone, often characterized by **swelling, draining sinuses, and grains** (microcolonies of the causative organism). - While it can be acquired via trauma, the typical presentation is much more **extensive and chronic** than the initial ulcerative nodule described.
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