Subcutaneous Mycoses — MCQs
"Medlar bodies" are seen in
A 40-year-old gardener presents with several subcutaneous nodules on his right hand, where he had cut himself on rose thorns, and physical examination reveals several erythematous fluctuant lesions. Which organism is most likely responsible for his condition?
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.
Match the following: A) Caplan syndrome- 1) Found first in coal worker B) Asbestosis- 2) Upper lobe predominance C) Mesothelioma- 3) Involves lower lobe D) Sarcoidosis- 4) Pleural effusion is seen
A farmer presents with a subcutaneous wound on his foot with discharge. Microscopy of a white granule from the wound shows Gram-positive filamentous rods. What is the most likely organism?
A patient walking barefoot during his morning walk has developed a swelling in the foot. What is the probable diagnosis?
Botryomycosis is a ___ disease
A 65-year old man presented with skin lesions on his chest and left arm and shoulder six weeks after returning from a vacation in Belize at the beach in the rain forest. The lesions occasionally stung, drained a dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. The larvae coming out of the pores are-
Subcutaneous Mycoses Indian Medical PG Practice Questions and MCQs
Question 1: "Medlar bodies" are seen in
- A. Coccidiomycosis
- B. Sporotrichosis
- C. Chromblastomycosis (Correct Answer)
- D. Histoplasmosis
Explanation: ***Chromblastomycosis*** - "**Medlar bodies**" (also known as muriform cells or sclerotic bodies) are characteristic findings in the tissue biopsy of patients with **chromoblastomycosis**. - These are thick-walled, septate, dark brown fungal cells that reproduce by septation and are crucial for the diagnosis of this chronic fungal infection. *Coccidiomycosis* - This deep fungal infection is characterized by thick-walled **spherules containing endospores** in tissue, rather than Medlar bodies [1]. - It primarily affects the lungs but can disseminate to other organs. *Sporotrichosis* - The classic histological finding in sporotrichosis is the presence of **cigar-shaped budding yeasts** in tissue, especially in the suppurative granulomas. - **Asteroid bodies**, which are yeasts surrounded by eosinophilic material, may also be seen. *Histoplasmosis* - This fungal infection is identified by small, **intracellular budding yeasts** (2-4 µm) found within macrophages in tissue samples [1]. - It commonly affects the lungs and can disseminate, particularly in immunocompromised individuals [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 717.
Question 2: A 40-year-old gardener presents with several subcutaneous nodules on his right hand, where he had cut himself on rose thorns, and physical examination reveals several erythematous fluctuant lesions. Which organism is most likely responsible for his condition?
- A. Aspergillus
- B. Malassezia
- C. Sporothrix (Correct Answer)
- D. Histoplasma
Explanation: ***Sporothrix*** - The gardener's history of a cut from rose thorns and the development of **subcutaneous nodules** are classic presentations of **sporotrichosis** (rose gardener's disease), caused by *Sporothrix schenckii*. - *Sporothrix schenckii* is a **dimorphic fungus** found in soil and on plant matter, causing localized cutaneous or subcutaneous lesions that typically follow **lymphatic spread** (lymphocutaneous pattern). *Aspergillus* - *Aspergillus* species typically cause **invasive pulmonary infections** (aspergillosis) in immunocompromised individuals or allergic bronchopulmonary aspergillosis. - While it can cause cutaneous infections, these are rare and usually occur in severely immunocompromised patients, without the classic "rose thorn" association. *Malassezia* - *Malassezia* species are yeasts that are normal skin flora and are primarily associated with **pityriasis versicolor**, **seborrheic dermatitis**, and **folliculitis**. - They do not typically cause deep subcutaneous nodules or are associated with puncture wounds from plants. *Histoplasma* - *Histoplasma capsulatum* is a **dimorphic fungus** that primarily causes **pulmonary infections** through inhalation of spores from soil contaminated with bird or bat droppings. - While it can rarely cause cutaneous lesions (especially in disseminated disease in immunocompromised patients), it is not associated with traumatic inoculation from plant material or the lymphocutaneous pattern seen here.
Question 3: 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 4: 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 5: 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 6: Match the following: A) Caplan syndrome- 1) Found first in coal worker B) Asbestosis- 2) Upper lobe predominance C) Mesothelioma- 3) Involves lower lobe D) Sarcoidosis- 4) Pleural effusion is seen
- A. A-3, B-4, C-2, D-1
- B. A-1, B-4, C-3, D-2 (Correct Answer)
- C. A-4, B-2, C-3, D-1
- D. A-2, B-4, C-3, D-1
Explanation: **A-1, B-4, C-3, D-2** - **Caplan syndrome** was first described in **coal workers** with **rheumatoid arthritis** and progressive massive fibrosis. - **Asbestosis** is often associated with **pleural effusion**, which can be benign or malignant. - **Mesothelioma** typically involves the **lower lobes** of the lungs, specifically the pleura, and is strongly linked to asbestos exposure. - **Sarcoidosis** is characterized by **non-caseating granulomas**, which have a predilection for the **upper lobes** of the lungs. *A-3, B-4, C-2, D-1* - This option incorrectly states that Caplan syndrome involves the lower lobe; **Caplan syndrome** is defined by the presence of large nodules in the lungs of coal workers with rheumatoid arthritis, and their specific lobar distribution is not a defining characteristic. - This option incorrectly states that Mesothelioma has an upper lobe predominance; **Mesothelioma** is a pleural malignancy and typically involves the **lower lobes**, extending along the pleura. *A-4, B-2, C-3, D-1* - This option incorrectly associates Caplan syndrome with pleural effusion; **Caplan syndrome** manifests as rheumatoid nodules in the lungs, not primarily pleural effusion. - This option incorrectly states that Asbestosis has an upper lobe predominance; **Asbestosis** predominantly affects the **lower lobes** of the lungs, causing interstitial fibrosis. *A-2, B-4, C-3, D-1* - This option incorrectly states that Caplan syndrome has an upper lobe predominance; the defining feature of **Caplan syndrome** is the combination of rheumatoid arthritis and pneumoconiosis, not specific lobar involvement. - This option correctly identifies pleural effusion with asbestosis and lower lobe involvement with mesothelioma, but **Caplan syndrome** is not characterized by upper lobe predominance.
Question 7: A farmer presents with a subcutaneous wound on his foot with discharge. Microscopy of a white granule from the wound shows Gram-positive filamentous rods. What is the most likely organism?
- A. Staphylococcus aureus
- B. Histoplasma
- C. Nocardia (Correct Answer)
- D. Sporothrix
Explanation: ***Nocardia*** - The presence of **white granules** in the discharge, along with **Gram-positive, filamentous rods**, is highly characteristic of *Nocardia* infection, often forming **sulfur granules** (though not always yellow). - *Nocardia* is a common soil bacterium, making it a likely pathogen in a **farmer with a subcutaneous wound** related to environmental exposure. *Staphylococcus aureus* - While *Staphylococcus aureus* can cause skin infections and abscesses, it presents as **Gram-positive cocci in clusters**, not filamentous rods. - It does not typically form **granules** in the discharge in the same manner as *Nocardia*. *Histoplasma* - *Histoplasma* is a **dimorphic fungus** that causes systemic infections, often acquired by inhaling spores. - It would appear as **yeast forms** in tissue or cultures, not Gram-positive filamentous rods, and is not typically associated with subcutaneous wounds forming granules. *Sporothrix* - *Sporothrix schenckii* causes **sporotrichosis**, characterized by a **subcutaneous nodule** that progresses along lymphatic channels. - It is a **dimorphic fungus** (yeast in tissue, mold in culture) and would not appear as Gram-positive filamentous rods on microscopy.
Question 8: A patient walking barefoot during his morning walk has developed a swelling in the foot. What is the probable diagnosis?
- A. Staphylococcus aureus
- B. Botryomycosis
- C. Tetanus
- D. Madura foot (Correct Answer)
Explanation: **Madura foot (Correct Answer)** - **Madura foot**, or mycetoma, is a **chronic granulomatous infection** often acquired through minor skin trauma, such as walking barefoot on contaminated soil - Classic presentation: **localized swelling, draining sinuses, and grain formation** - The image shows a **swollen foot** with signs of chronic infection, consistent with the progressive nature of Madura foot affecting subcutaneous tissues and eventually bone - Endemic in tropical regions including India, making this the most likely diagnosis given barefoot walking *Staphylococcus aureus (Incorrect)* - While *S. aureus* can cause various skin infections and swelling, it typically presents with **acute infections** (abscesses, cellulitis, folliculitis) - A **chronic, localized swelling with potential sinus tracts** that progresses over time is less typical for uncomplicated *S. aureus* infections - The context of barefoot walking on soil is more suggestive of fungal or actinomycotic infections *Botryomycosis (Incorrect)* - **Botryomycosis** is a rare chronic bacterial infection that causes granulomas and abscesses, often with "grains" similar to mycetoma - Typically caused by bacteria like *Staphylococcus aureus* or *Pseudomonas aeruginosa*, **not typically acquired directly from soil** - Though it presents with granulomas and "grains," the context of walking barefoot and the endemic nature of mycetoma in India makes Madura foot more likely *Tetanus (Incorrect)* - **Tetanus** is a severe neurological condition caused by the toxin of *Clostridium tetani*, entering through wounds - Presents with **muscle spasms, rigidity, and lockjaw** (trismus) - Does **not cause localized swelling or chronic granulomatous lesions** as shown in the image - Wrong clinical presentation entirely
Question 9: Botryomycosis is a ___ disease
- A. Viral
- B. Bacterial (Correct Answer)
- C. Parasitic
- D. Fungal
Explanation: ***Bacterial*** - **Botryomycosis** is primarily a **bacterial infection**, commonly caused by *Staphylococcus aureus* or, less frequently, by gram-negative bacteria like *Pseudomonas aeruginosa*. - It presents as chronic suppurative granulomatous inflammation characterized by the presence of **"grains" or "granules"** composed of bacterial microcolonies surrounded by hyaline material. *Viral* - **Viral infections** are caused by viruses and are typically characterized by intracellular replication and various cytopathic effects. - Botryomycosis does not involve viral pathogens; its pathogenesis is entirely distinct from viral diseases. *Parasitic* - **Parasitic diseases** are caused by parasites such as protozoa, helminths, or ectoparasites. - The clinical and pathological features of botryomycosis, including the distinct bacterial grains, do not align with parasitic infections. *Fungal* - Although it can superficially resemble **mycetoma (a fungal infection)** due to the presence of "grains," botryomycosis is not caused by fungi. - Mycetoma involves fungal organisms like *Madurella mycetomatis* or *Actinomadura madura*, which are distinctly different from the bacterial agents of botryomycosis.
Question 10: A 65-year old man presented with skin lesions on his chest and left arm and shoulder six weeks after returning from a vacation in Belize at the beach in the rain forest. The lesions occasionally stung, drained a dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. The larvae coming out of the pores are-
- A. Loa loa
- B. Diphyllobothrium latum
- C. Dermatobia hominis (Correct Answer)
- D. Dracunculus medinensis
Explanation: ***Dermatobia hominis*** - The description of **cutaneous nodules** with a central pore from which a **moving larva** is observed, particularly after travel to a tropical region like Belize, is classic for **furuncular myiasis** caused by **Dermatobia hominis** larvae (human botfly). - The **"occasional stinging"** and **"dark exudate"** are characteristic symptoms of the larva burrowing in the skin and secreting waste products. *Loa loa* - **Loa loa** (African eye worm) is a filarial nematode that migrates through **subcutaneous tissues** and occasionally across the eye, causing **Calabar swellings**. - It does not present as a **furuncular lesion** with a visible central moving larva emerging from a pore. *Diphyllobothrium latum* - **Diphyllobothrium latum** is a **tapeworm** that infects the intestines and is acquired by consuming undercooked infected fish. - It causes gastrointestinal symptoms and can lead to **vitamin B12 deficiency**, but it does not produce **skin lesions with moving larvae**. *Dracunculus medinensis* - **Dracunculus medinensis** (guinea worm) infection typically results in a **painful blister** on the lower limbs, from which the female worm emerges to release larvae when exposed to water. - While it involves a skin lesion, the presentation of **multiple nodules with a central pore revealing a moving larva** is not consistent with **dracunculiasis**.
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