Tropical Mycoses — MCQs
Which of the following is NOT a fungal infection?
Medlar bodies are found in -
Histoplasma capsulatum, a dimorphic fungus found in soil heavily contaminated with bird droppings, is identified in tissue biopsies by which of the following characteristics?
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 farmer presents with multiple dicharging sinuses in the leg not responding to antibiotics. Most likely diagnosis is -
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 42-year-old Bengali male presents with painless nodules over the face. The face is erythematous, and the surface of some of the large nodules is discolored. He gives a history of an insect bite in the past while he went to the jungle for work. What is the most likely diagnosis?
The skin condition shown in the image is associated with?
Which of the following conditions is characterized by the sign of the groove?
A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
Tropical Mycoses Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is NOT a fungal infection?
- A. Black Piedra
- B. White Piedra
- C. Tinea nigra Palmaris
- D. Mycoses fungoides (Correct Answer)
Explanation: ***Mycoses fungoides*** - This is a type of **cutaneous T-cell lymphoma**, which is a **malignancy of lymphocytes**, not a fungal infection [1]. - It presents with skin lesions that can mimic various dermatological conditions but is characterized by abnormal T-cells infiltrating the skin [1], [2]. *Black Piedra* - This is a superficial fungal infection of the **hair shaft** caused by **Piedraia hortae**, forming hard, black nodules. - It is an example of a **dermatomycosis**. *White Piedra* - This is a fungal infection of the **hair shaft** caused by **Trichosporon species**, leading to soft, white to light brown nodules. - Like black piedra, it is also a **dermatomycosis**. *Tinea nigra Palmaris* - This is a superficial fungal infection of the **stratum corneum** of the skin, primarily on the palms and soles, caused by **Hortaea werneckii**. - It presents as irregular, darkly pigmented (brown to black) macules and is a true **mycosis**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 613-614. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 564-565.
Question 2: Medlar bodies are found in -
- A. Chromoblastomycosis (Correct Answer)
- B. Mycetoma
- C. Histoplasmosis
- D. Sporotrichosis
Explanation: ***Chromoblastomycosis*** - **Medlar bodies**, also known as **sclerotic bodies** or **copper pennies**, are thick-walled, septate, dematiaceous fungal cells characteristic of chromoblastomycosis. - They are typically found within **giant cells** or extracellularly in the dermis during histological examination of infected tissue. *Mycetoma* - Characterized by the presence of **grains** or **granules** composed of aggregated fungal hyphae (eumycetoma) or bacterial filaments (actinomycetoma) within the tissue [2]. - It presents as a chronic, progressive infection involving the skin, subcutaneous tissue, and often underlying bone [2]. *Histoplasmosis* - Caused by **_Histoplasma capsulatum_**, a dimorphic fungus that appears as small, oval, budding yeast cells within **macrophages** in infected tissues [1]. - It primarily affects the lungs but can disseminate to other organs, especially in immunocompromised individuals [1]. *Sporotrichosis* - Caused by **_Sporothrix schenckii_**, which appears as small, cigar-shaped budding yeast forms or asteroid bodies (yeast cells surrounded by an eosinophilic cuticle) in tissue. - It typically presents as **lymphocutaneous lesions** following traumatic inoculation of fungal spores [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, p. 717. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 393-394.
Question 3: Histoplasma capsulatum, a dimorphic fungus found in soil heavily contaminated with bird droppings, is identified in tissue biopsies by which of the following characteristics?
- A. Yeasts with broad-based buds
- B. Single-cell yeasts with pseudohyphae
- C. Arthrospores
- D. Oval budding yeasts within macrophages (Correct Answer)
Explanation: ***Oval budding yeasts within macrophages*** - In tissue biopsies, **Histoplasma capsulatum** characteristically appears as small, **oval-shaped budding yeasts** that are predominantly found **intracellularly within macrophages**. - This intracellular location is a key diagnostic feature, as the organism can survive and multiply inside these phagocytic cells. *Yeasts with broad-based buds* - This description is characteristic of **Blastomyces dermatitidis**, another dimorphic fungus, which displays large yeasts with a single broad-based bud in tissue. - Unlike *Histoplasma*, **Blastomyces** yeasts are typically much larger and not necessarily intracellular. *Single-cell yeasts with pseudohyphae* - This morphology is characteristic of **Candida albicans**, particularly in its pathogenic forms within tissues. - **Candida** forms true hyphae and pseudohyphae, and its yeasts do not typically reside within macrophages in the same manner as *Histoplasma*. *Arthrospores* - **Arthrospores** (also called arthroconidia) are characteristic of fungi like **Coccidioides immitis**, which appear as barrel-shaped structures in laboratory cultures, but *spherules containing endospores* are seen in tissue. - **Histoplasma** does not form arthrospores in human tissue; it forms yeasts.
Question 4: 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 5: A farmer presents with multiple dicharging sinuses in the leg not responding to antibiotics. Most likely diagnosis is -
- A. Nocardia
- B. Actino-mycetoma
- C. Madurella (Correct Answer)
- D. Sporothrix
Explanation: ***Madurella*** - This symptom complex, particularly **multiple discharging sinuses** in an agricultural worker not responding to antibiotics, is highly suggestive of **eumycetoma (true mycetoma)**. - **Madurella** species (e.g., *Madurella mycetomatis*) are the most common cause of eumycetoma, which is characterized by chronic subcutaneous infection with discharge of **grains** containing fungal elements. *Nocardia* - **Nocardia** causes **actinomycetoma**, which also presents with discharging sinuses and grains but is caused by filamentous bacteria, not fungi. - While *Nocardia* can produce similar lesions, the distinction often requires microscopic examination of the grains or culture, and the context often points to true fungi in geographical areas where Madurella is prevalent. *Actino-mycetoma* - **Actinomycetoma** refers to mycetoma caused by **filamentous bacteria** (e.g., *Nocardia, Actinomadura, Streptomyces*), which produces different types of grains and responds to different antibiotic regimens. - The question implies a lack of response to typical antibiotics, subtly suggesting a fungal etiology which is generally less responsive to standard antibacterial treatments. *Sporothrix* - **Sporothrix schenckii** causes **sporotrichosis**, which typically presents as a **lymphocutaneous infection** with a primary lesion that may ulcerate and spread along lymphatic channels, rather than extensive, chronic discharging sinuses with grains characteristic of mycetoma. - While it can occur in agricultural workers due to inoculated trauma (e.g., thorn pricks), its clinical presentation is distinct from mycetoma.
Question 6: 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.
Question 7: A 42-year-old Bengali male presents with painless nodules over the face. The face is erythematous, and the surface of some of the large nodules is discolored. He gives a history of an insect bite in the past while he went to the jungle for work. What is the most likely diagnosis?
- A. Chronic Fungal infections
- B. Cutaneous Leishmaniasis (Correct Answer)
- C. Cutaneous tuberculosis
- D. Leprosy
Explanation: ***Cutaneous Leishmaniasis*** - The presentation of **painless erythematous nodules** on the face, especially in a person with a history of **insect bites** and exposure to a **jungle environment** (where sandflies, vectors of Leishmania, are common), strongly suggests cutaneous leishmaniasis. - The discoloration of the surface of large nodules is also consistent with the typical appearance of **chronic cutaneous leishmaniasis lesions**. *Chronic Fungal infections* - While chronic fungal infections can cause skin nodules, they typically present with features like **scaling, itching, or satellite lesions**, which are not described here. - The specific history of **insect bites** and geographical context points away from common fungal etiologies. *Cutaneous tuberculosis* - Cutaneous tuberculosis can manifest as nodules (**lupus vulgaris** or **scrofuloderma**), but these are often associated with other signs of tuberculosis, such as **pulmonary involvement** or **lymph nodal enlargement**, and typically have a slower progression. - The history of **insect bite** is not a primary risk factor for cutaneous tuberculosis. *Leprosy* - Leprosy, particularly **lepromatous leprosy**, can cause extensive facial nodules, but these are often associated with **nerve involvement** leading to sensory loss, and the lesions tend to be diffusely infiltrative rather than discrete, discolored nodules. - The rapid onset or history of a single insect bite is less characteristic of leprosy, which has a very **long incubation period**.
Question 8: The skin condition shown in the image is associated with?
- A. Diabetes mellitus (Correct Answer)
- B. Hypothyroidism
- C. Hyperthyroidism
- D. Sarcoidosis
Explanation: ***Diabetes mellitus*** - The image shows **diabetic dermopathy** (also known as "shin spots"), which presents as hyperpigmented, atrophic macules or papules, usually on the shins. This condition is a common cutaneous manifestation of **diabetes mellitus**. - Other dermatological conditions associated with diabetes include **necrobiosis lipoidica diabeticorum**, **acanthosis nigricans**, and **erythrasma**, which are important to recognize in patients with diabetes. *Hypothyroidism* - Hypothyroidism is associated with **myxedema**, which typically manifests as non-pitting edema, dry and coarse skin, and hair loss. - While it can cause skin changes, it does not typically present with the pigmented, atrophic lesions seen in the image. *Hyperthyroidism* - Hyperthyroidism can cause skin changes such as **pretibial myxedema** (a specific form of localized skin thickening, typically on the shins, that is often associated with Graves' disease) and warm, moist skin due to increased metabolism. - The lesions shown in the image are not consistent with the typical presentation of pretibial myxedema or other hyperthyroid skin manifestations. *Sarcoidosis* - Sarcoidosis can present with various skin lesions, including **erythema nodosum**, lupus pernio, plaques, and papules. - The skin changes seen in the image, characterized by small, atrophic, hyperpigmented macules, do not fit the typical pattern of cutaneous sarcoidosis.
Question 9: Which of the following conditions is characterized by the sign of the groove?
- A. Lymphogranuloma venereum (Correct Answer)
- B. Granuloma inguinale
- C. Syphilis
- D. Chancroid
Explanation: **Explanation:** **Lymphogranuloma venereum (LGV)** is caused by the **L1, L2, and L3 serovars of *Chlamydia trachomatis***. The "Sign of the Groove" (Greenblatt’s sign) is a pathognomonic clinical finding in the secondary stage of LGV. It occurs when the inguinal and femoral lymph nodes enlarge simultaneously, separated by the rigid **inguinal ligament**. This creates a visible depression or "groove" between the two groups of inflamed lymph nodes. **Analysis of Incorrect Options:** * **B. Granuloma Inguinale (Donovanosis):** Caused by *Klebsiella granulomatis*. It presents with painless, beefy-red, velvety ulcers. It is characterized by "pseudobuboes" (subcutaneous granulation tissue) rather than true lymphadenopathy. * **C. Syphilis:** Primary syphilis presents with a painless, indurated "hard chancre." While it causes bilateral inguinal lymphadenopathy, the nodes are discrete, rubbery, and do not form a groove. * **D. Chancroid:** Caused by *Haemophilus ducreyi*. It presents with painful, soft ulcers and painful inflammatory buboes that are usually unilateral and may suppurate, but they do not form the characteristic groove sign. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of LGV:** Primary (painless papule/ulcer), Secondary (Inguinal syndrome with the Groove sign), and Tertiary (Genito-anorectal syndrome/Elephantiasis). * **Diagnosis:** Frei test (historical), NAAT (current gold standard), and **Donovan bodies** (safety-pin appearance) are seen in Donovanosis, NOT LGV. * **Treatment:** Doxycycline (100 mg BID for 21 days) is the drug of choice for LGV.
Question 10: A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
- A. Sweet's Syndrome
- B. Erythema nodosum (Correct Answer)
- C. Erythema nodosum leprosum
- D. Behcet's syndrome
Explanation: ### Explanation **Correct Answer: B. Erythema nodosum** **Why it is correct:** Erythema nodosum (EN) is the most common form of **septal panniculitis**. Clinically, it presents as tender, erythematous nodules typically located over the **pretibial area (shins)**, often accompanied by fever and malaise. Histopathologically, early lesions show edema and neutrophilic infiltration of the septa. As the lesion evolves, it is characterized by **Miescher’s radial granulomas**—small clusters of spindle-shaped or **foamy histiocytes** surrounding a central cleft. The absence of vasculitis is a hallmark feature that distinguishes EN from other forms of panniculitis. **Why the other options are incorrect:** * **A. Sweet’s Syndrome:** This is a neutrophilic dermatosis characterized by "juicy" erythematous plaques and high fever. Histology shows dense dermal neutrophilic infiltrate with papillary dermal edema, but it is not a primary panniculitis and does not typically present with foamy histiocytes in the septa. * **C. Erythema nodosum leprosum (ENL):** While ENL also presents with tender nodules and fever, it is a Type 2 Lepra reaction. Histologically, it is a **lobular panniculitis** and, crucially, it **must show evidence of vasculitis** (leukocytoclastic vasculitis) and the presence of *M. leprae* (AFB positive). * **D. Behcet’s syndrome:** While it can cause EN-like lesions, the systemic involvement (oral/genital ulcers, uveitis) and the characteristic histopathology (often showing vasculitis) do not fit the isolated description provided. **NEET-PG High-Yield Pearls:** * **Most common cause of EN:** Idiopathic (followed by Streptococcal infections, Sarcoidosis, and TB). * **Histopathology Key:** Septal panniculitis **without** vasculitis = Erythema Nodosum. * **Löfgren Syndrome:** Triad of EN, bilateral hilar lymphadenopathy, and arthritis (highly suggestive of Sarcoidosis). * **Miescher’s Radial Granulomas:** Pathognomonic histological finding for EN.
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