Diagnostic Challenge: LD Bodies vs Pneumocystis Vs Histoplasma in Giemsa-Stained BAL

Found in Giemsa staining of BAL. Possible pathogen?

Morphological Features (Center)

• A dense, violet-stained cluster of small, round to oval intracellular structures.
• Surrounded by a faint cellular boundary suggestive of foamy macrophage cytoplasm.
• The inclusion-like structures may appear as dot-like or crescentic bodies.

Possible Pathogen

• The structure is suggestive of Pneumocystis jirovecii (formerly P. carinii), a fungal pathogen seen in immunocompromised patients, especially in:
  • HIV/AIDS
  • Post-transplant
  • Cancer chemotherapy

Supporting Features for Pneumocystis

• Giemsa stain may highlight:
  • Foamy exudate (“cotton candy” appearance) in alveolar spaces
  • Trophozoites or cyst-like forms (difficult to confirm without a silver stain or immunofluorescence)

Recommendations

• Confirm with Gomori methenamine silver (GMS) or an immunofluorescent stain specific for Pneumocystis.
• Consider PCR for Pneumocystis jirovecii for high sensitivity, especially in cancer patients with atypical pneumonia.

Is it possible to be LD bodies?

Based on the Giemsa-stained BAL image:

The central violet-stained cluster of intracellular forms could resemble Leishman-Donovan (LD) bodies, especially in their:

• Small, round to oval intracellular appearance,
• Presence within macrophage-like host cells.

LD Bodies vs. Pneumocystis jirovecii – Key Differentiating Points

Feature	LD Bodies (Leishmania donovani)	Pneumocystis jirovecii
Seen in	Kala-azar / Visceral leishmaniasis	Immunocompromised patients (HIV, cancer, etc.)
Host cell	Inside macrophages	Alveolar foamy exudate or inside macrophages
Size & shape	2–4 µm, oval with nucleus + kinetoplast	Round to oval, sometimes crushed cysts or foamy
Stain (Giemsa)	Clear nucleus and rod-shaped kinetoplast	Diffuse cytoplasmic stain without kinetoplast
Preferred sample	Bone marrow, splenic aspirate, blood smears	BAL fluid (best for Pneumocystis)
Geographic relevance	Endemic in Terai/Nepal (esp. Leishmaniasis)	Widespread, especially in HIV/TB coinfection

Conclusion

• LD bodies are possible, but less likely in BAL samples unless:
  • There is a systemic dissemination of leishmaniasis involving the lungs (very rare).
• Pneumocystis jirovecii remains more probable given:
  • The specimen (BAL),
  • The patient context (cancer),
  • The cluster pattern and cytoplasmic clearing.

Recommendation

To differentiate confidently:

• Perform Giemsa at higher magnification (1000X) to check for:
  • Kinetoplast + nucleus = LD body
• Consider PCR or special stains:
  • For Pneumocystis: GMS stain or PCR
  • For Leishmania: PCR or splenic/bone marrow aspirate

Note: The above image of mag.1000X with 4X optical zoom

Image: Giemsa stain, BAL specimen

Magnification: 1000X with 4X optical zoom
This level of detail supports close examination of intracellular structures.

Key Observations

• Intracellular clusters within a macrophage-like cell
• Oval to round basophilic (purple) bodies
• Some appear to have two internal structures, suggesting:
  • A nucleus and possibly a kinetoplast (characteristic of Leishmania donovani amastigotes)

Interpretation

Leishman-Donovan (LD) bodies are strongly possible, based on:

• Giemsa staining characteristics
• Presence of:
  • Central nucleus
  • Rod-shaped kinetoplast
• Intracellular clustering in a host cell (likely macrophage)
• High-resolution morphology (1000X + zoom) supports this ID

But Consider

Although rare, pulmonary leishmaniasis has been reported—especially in immunocompromised patients (e.g., cancer, HIV). In such patients, LD bodies can appear in BAL.

Suggested Confirmatory Steps

1. Repeat smear and examine multiple fields under oil immersion.
2. Perform PCR or rK39 serology for Leishmania if clinically suspected.
3. Rule out Pneumocystis or Histoplasma, which may also mimic.

Conclusion

The morphology seen in this high-magnification Giemsa-stained BAL is consistent with Leishman-Donovan bodies. While rare in the lung, it is possible in immunocompromised or disseminated cases. Further confirmation with molecular or serologic tests is advisable.

A comparison chart or flowchart to distinguish LD bodies from other intracellular pathogens (like Histoplasma or Pneumocystis)

Comparison Chart: LD Bodies vs Histoplasma vs Pneumocystis

Feature	Leishman-Donovan (LD) Bodies	Histoplasma capsulatum	Pneumocystis jirovecii
Size	2–4 μm	2–5 μm	4–7 μm (cyst); 1–3 μm (troph)
Location	Intracellular (macrophages)	Intracellular & extracellular	Alveolar exudates, sometimes within macrophages
Shape	Oval with nucleus + rod-shaped kinetoplast	Small oval or round yeast-like cells	Cysts are cup-shaped or crushed-disc; trophs are irregular
Staining (Giemsa)	Blue nucleus + pink kinetoplast	Blue cytoplasm, small central basophilic dot	Foamy appearance; pale or faint stain
Preferred Host Cell	Macrophage cytoplasm	Macrophage cytoplasm	Exudates or alveolar lining
Associated Disease	Visceral leishmaniasis (Kala-azar)	Histoplasmosis	Pneumocystis pneumonia (PCP)
Geographic Link	Terai (Nepal), India, Africa	Endemic in river valleys (US, Asia)	Worldwide (esp. HIV/AIDS, transplant)
Special Stains	Giemsa, rK39 serology, PCR	PAS, GMS, culture	GMS, DFA, PCR
Clinical Clues	Fever, hepatosplenomegaly, pancytopenia	Cough, weight loss, mediastinal lymphadenopathy	Dry cough, hypoxia, bilateral infiltrates

Diagnostic Flowchart: Intracellular Bodies in BAL (Giemsa)

        BAL smear → Giemsa stain (1000X + Zoom)
                      │
                      ▼
        Small intracellular round/oval structures observed
                      │
     ┌────────────────┼─────────────────┐
     ▼                ▼                 ▼
 LD bodies?     Histoplasma?     Pneumocystis?
     │                │                 │
 Nucleus +           Tiny yeast       Foamy exudate
 rod kinetoplast     like dots        Crushed disc/cyst forms
 in macrophages      in macrophages   no clear nucleus
     │                │                 │
     ▼                ▼                 ▼
 rK39 / PCR     PAS / GMS stain     GMS / DFA / PCR
 Spleen/BM      Culture, antigen    BAL PCR, silver stain
 aspirate       detection           (confirmatory)

Summary Points

• LD Bodies = Nucleus + kinetoplast; macrophage-bound.
• Histoplasma = Tiny budding yeasts; PAS/GMS positive.
• Pneumocystis = No budding; foamy matrix; best with GMS or DFA.

Further Readings

• https://pmc.ncbi.nlm.nih.gov/articles/PMC11898755/
• https://onlinelibrary.wiley.com/doi/10.1002/dc.24280
• https://www.researchgate.net/publication/11200058_Comparison_of_methods_for_identification_of_Pneumocystiscarinii_in_bronchoalveolar_lavage_fluid
• https://pmc.ncbi.nlm.nih.gov/articles/PMC5490308/
• https://pubmed.ncbi.nlm.nih.gov/31322837/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC4920866/
• https://www.semanticscholar.org/paper/Diagnosis-of-Pneumocystis-pneumonia-by-lavage-at-a-Dahiya-Mathur/abf10505a51caefd2687f8c074d49476d37d37c8
• https://journals.lww.com/cddr/fulltext/2022/06010/diagnosis_of_post_kala_azar_dermal_leishmaniasis.17.aspx
• https://www.mdpi.com/2309-608X/9/8/812
• https://www.pathologyoutlines.com/topic/skinnontumorleishmaniasis.html