This document discusses various fungal infections of the chest and their imaging appearances. It provides an overview of 9 main fungal organisms (Histoplasmosis, Coccidioidomycosis, Blastomycosis, Paracoccidioidomycosis, Candidiasis, Pneumocystis, Cryptococcosis, Mucormycosis, Aspergillosis) and summarizes their typical radiographic or CT findings. These include calcified nodules, cavitating lesions, consolidations, ground glass opacities, and halo signs which help differentiate the fungal pathogens.

1. Imaging in
Fungal Infections of Chest
Dr. Gobardhan Thapa
Resident, First year
Radiodiagnosis,
NAMS, Bir Hospital
Nepal

2. Outline of Presentation
• Introduction
• Classification of Fungal Infections
• Overview of specific Fungal organism and the
current Imaging modalities
• Summary
• references

3. A case report
• A 71-year-old Chinese male was admitted with complaint of
chronic cough and malaise for two months. He had been in
Tucson, Arizona, USA, visiting for four months right before
the symptoms occurred. He had transient low-grade fever,
but denied hemoptysis, night sweats, skin rashes, or
headache. He did not smoke or abuse drugs. Physical
examination revealed no abnormalities. Lab tests showed
an elevated erythrocyte sedimentation rate (ESR) of 46
mm/h, while complete blood count (CBC), eosinophil count,
serum chemistry, and tumor biomarkers were all in normal
range. Human immunodeficiency virus (HIV) antibody was
found to be negative. Sputum culture showed normal flora
growth.

4. • Chest computed tomographic (CT) scan revealed
an irregular-margined opacity measuring 3.0
cm×3.8 cm in diameter in the sub-pleura region of
right middle lobe. Right hilar and mediastinal
lymphadenopathy was noted. Lung cancer was
considered as the most likely diagnosis.
Subsequent bronchoscopy and brush cytology
were negative. The patient received a procedure
of right middle lobe and lower lobectomy on the
eighth day after admission.

5. Chest computed tomographic (CT) scan

6. -Journal of Zhejiang university science, April, 2014
• Histopathological examination of lung specimen
showed focal necrotic granulomatous
inflammation with multinucleated giant cells
containing fungal spherules and infiltrations of
massive neutrophils, eosinophils, and
lymphocytes.. The final diagnosis thus was
confirmed pathologically as pulmonary
Coccidioides infection. The patient was totally free
from discomfort in the course of two years follow-
up after the lobectomy

7. Introduction
• Fungal Pneumonia
– Are now seen with increased frequency
• Increase in the incidence of disease caused by pathogenic
fungi in healthy hosts
• Emergence of opportunistic species in immuno-
compromsied hosts

8. Fungal Infections:
Saprophytic Fungi
Candidiasis
Pneumocystis
Cryptococcosis
Mucormycosis
Aspergillus
Pathogenic Fungi
Histoplasmosis
Coccidioidomycosis
Blastomycosis
Paracoccidioidomycosis
In all cases, fungi elicit a “Necrotizing granulomatous reaction”

9. 1. Histoplasmosis
• Histoplasma capsulatum
• In moist soil and bird/bat excreta
• Mostly subclinical infection:
– Heals spontaneously
– CXR: may be normal
• Or sometimes well-defined, calcific nodules <1 mm in size
• Calcified hilar of mediastinal nodes
• Multiple miliary calcified nodules

10. • Progression of the infective foci:
– Leading to a larger nodule
– Hilar nodes enlargement is common
– Locally progressive: may have consolidative changes,
later associated with Fibrosis and cavitation.
• Massive inhalation of organisms:
– May show fairly discrete, nodular opacities 3-4 mm in
diameter with hilar adenopathy

11. Fig. acute histoplasmosis
widespread bilateral well-defined 3-5 mm nodules

12. Fig. disseminated histoplasmosis in a HIV patient
axial CT shows multiple small pulmonary nodules distributed
uniformly throughout the both lungs

13. Fig. Histoplasmosis
incidental finding of multiple calcified
pulmonary nodules

14. • Histoplasmoma:
– A solitary, sharply defined nodule <3 cm
– Most common in lower lobes-frequently calcify
• Fibrosing Mediastinitis (chronic pulmonary disease):
– Uncommon late manifestation
– Stenosis of venacava, oesophagus, trachea, bronchi or
central pulmonary vessels
– CXR: widened mediastinum

15. Fig. Histoplasmoma
Axial CT shows right lower lobe Histoplasmoma with central
calcification

16. Fig. fibrosing mediastinitis following Histoplasmosis
radiographs shows widening of the mediastinum

17. • blood-borne dissemination
– Asymptomatic blood-borne dissemination is common
– Eg calcified granulomas in patients of endemic area
– Clinically apparent disseminated histoplasmosis
• Extremely rare

18. 2. Coccidioidomycosis
• Coccidioides immitis
• Found in soil in arid/semi-arid areas
• 4 types of clinical and radiographic pulmonary
infections:
a) Acute Coccidioidomycosis
b) Persistent Coccidioidomycosis
c) Chronic progressive disease
d) Disseminated (Miliary) Coccidioidomycosis

19. a) Acute coccidioidomycosis
• Develops in 40% of infected adults
• Self-limiting viral type illness: Valley fever
• Associated with erythema nodosum and Arthralgia
• CXR: may be normal or
 Focal or multifocal segmental air-space opacities
 Associated with Hilar and mediastinal adenopathy and pleural
effusion
b) Persistent coccidioidomycosis (infection beyond 6-8
weeks)
• Coccidioidal masses or nodules (coccidioidomas)
• Areas of round pneumonia- subpleural regions of upper lobes
• Cavitate rapidly-produce characteristic thin-walled cavities

20. c) Chronic progressive disease
• Upper lobe fibro-cavitatory disease
– Thin-walled cyst : Grape-skin sign
• Similar to Post-primary TB and Histoplasmosis
d) Disseminated (Miliary) coccidioidomycosis
• Relatively rare
• Affects the immuno-compromised patients

21. Fig. coccidioidomycosis
a non-specific patch of consolidation present in left lower
lobe. One year later a thin-walled cavity is evident

22. Fig. primary coccidioides infection
frontal radiograph in a female with a clinical diagnosis of
valley fever reveals a mass like opacity in the right lower
lung with enlarged right hilar nodes

23. Fig. primary coccidioides infection
coronal reformatted CT of same patient
confirms a right middle lobe nodule

24. Fig. Chest x-ray showing Grape-skin sign
thin-walled grape-skin cyst
over time cavity may deflate and acquire slightly thicker wall

25. 3. Blastomycois
• Caused by Blastomyces dermatidis
• Chronic systemic disease
• Primarily affects the lungs and the skin
• Pulmonary infections often asymptomatic
• Symptomatic infection:
– Resembles that of an Acute bacterial pneumonia

26. • Radiographically:
– Usually non-specific
• Most common presentation:
– Homogeneous non-segmental air space opacification with
propensity for upper lobes
• Less common presentation:
– Single or multiple masses
– Cavitate in 15% of cases
– Tend to occur in patients with prolonged symptoms (1
months)-may mimic Bronchogenic Ca

27. • Less common presentation:
– Diffuse reticulo-nodular opacities
• Pleural effusion and lymph node enlargement –
uncommon
• Disseminated miliary form
– In immunocompromised hosts

28. Fig. Blastomyces dermatidis infection
chest radiograph shows an ill-defined mass in the left upper
lobe. CT scan through the upper lobes shows an irregular mass
in the left upper lobe with surrounding ground glass opacity.
Biopsy revealed Blastomyces dermatidis infection

29. 4. Paracoccidioidomycosis(PCM)
• Also known as South American Blastomycosis
• Endemic disease caused by dimorphic fungi
– Paracoccidioides brasiliensis
• Most frequent systemic mycosis in Latin America
esp. in Brazil
• HRCT:
– Areas of ground-glass opacities, nodules, interlobular
septal thickening, air-space consolidation, cavitation
and fibrosis

30. 5. Candidiasis
• Candida albicans
• Important pathogen esp. in Immunocompromised
patients:
– Particularly in patients with underlying malignancy, IV
drugs abuser, AIDS, following Bone marrow transplant
• Lung infection is usually due to hematogeneous
spread

31. • Radiographically, may present as
– Chronic pneumonia
– Abscess formation
– Mycetoma formation
• CT
– Multiple bilateral nodular opacities often associated with
areas of consolidation and ground glass opacities-CT halo
sign
• Less common presentations:
– Pleural effusion, thickening of bronchial walls, cavitation

32. Fig. disseminated candidiasis with CT halo
sign

33. 6. Pneumocystis jiroveci
• Opportunistic fungal pathogen
• Cause pneumonia in patients with
– AIDs
– Organ transplant
– Undergoing chemotherapy
– Immunosuppressive treatment
– Long term corticosteroids

34. • Radiographically,
– May have normal findings
– Classic features: diffuse, bilateral interstitial infiltrates in
peri-hilar distribution
• CT:
– Done in a highly suspicious case for confirming the
diagnosis
– Peri-hilar ground glass opacities, in a patchy or geographic
distribution with areas of superimposed interlobular septal
thickening: Crazy Paving pattern
– May rapidly progress to involve entire lung

35. Fig. Pneumocystis Pneumonia in an HIV patient:
Crazy paving sign

36. • Complications:
– Thin-walled cavities
– Pneumothorax
• Less common presentations
– pleural effusion, nodules, miliary disease, calcified
lymph nodes

37. 7. Cryptococcosis (Torulosis)
• Cryptococcus neoformans (yeast form fungi)
• Found in soil or bird droppings
• Mostly asymptomatic
• Cryptococcal pneumonia
– Common in AIDS (when CD4 <100/cu. mm)

38. • Chest radiography:
– Homogeneous, segmental or lobar opacifications
– Miliary, reticular or reticulo-nodular interstitial
patterns
– Pulmonary masses-5 mm to large (usually pleura-
based) with ill-defined edge known as Torulosis
• May show Halo sign
• May cavitate
– Lymph node enlargement and calcification is unusual

39. Fig. cryptococcus
a pleurally based mass like area of consolidation in the left
upper lobe is present in a patient who also had cryptococcal
meningitis

40. 8. Mucormycosis
• Opportunistic fungal infection of order Mucorales
• Broad, non-septated hyphae that randomly branch
at right angles
• Spreading destructive infections in Diabetics and
immuno-compromised

41. • Radiographically,
– Lobar or multi-lobar areas of consolidation and solitary or
pulmonary nodules and masses with Cavitation in 26-40 %
cases-air crescent sign suggestive of invasive fungal
infection in 5-12.5 % cases
• Dense cavitating bronchopneumonia
• CT:
– Non-specific
– Solitary or multiple areas of consolidation or
– solitary of multiple nodules surrounded by a Halo of
ground-glass attenuation and cavitation

42. Fig. pulmonary mucormycosis in a patient
reverse halo or bird nest or Atoll sign
axial (left) and coronal (right) images show peripheral rim of consolidation
surrounding central ground glass opacity, reticulation and nodularity

43. 9. Aspergillus infection
• Caused by Aspergillus species, usually A.
fumigatus
• Can take different forms, depending on an
individual’s immune response to the organism,
classically:
– Aspergilloma or Mycetoma formation or Saprophytic
forms
– Invasive forms
– Allergic forms

44. Aspergilloma
• Also known as fungus ball
• a ball of hyphae, mucus and cellular debris that
colonizes a pre-existing bulla or a parenchymal cavity
created by some other pathogen or destructive
process
• Invasion into lung parenchyma does not occur unless
the host defense mechanisms are compromised
• Usually asymptomatic
• May cause Hemoptysis-which can be massive

45. • Radiographs or CT findings:
– Solid round mass within an upper
lobe cavity, with an area of Air-
crescent separating the mycetoma
from the cavity wall- roll
dependently on decubitus
radiographs
– Progressive apical pleural
thickening adjacent to a cavity is
common
• should prompt a search for a
complicating mycetoma

46. Fig. Air-crescent or Monad sign of Aspergillus
gravity dependence of fungus ball

47. Semi-invasive or Chronic necrotizing Aspergillosis
• In patients with mildly impaired immunity e.g.
Chronic illness, Diabetes, malnutrition, alcoholism,
advanced age, steroid administration, chronic
obstructive disease
• Radiographically- variable appearance
– Most common:
• One or more rounded, poorly marginated areas of homogeneous
opacification with or without Air-bronchograms and or cavitation
• With time, the lesions margins may become discrete
– May resemble a mass

48. Fig. aspergillosis
a necrotizing pneumonia in both lower zones has
cavitated mimicking the formation of fungus balls

49. Invasive Aspergillosis
• Angio-invasive:
– Occlusion of small-to-medium pulmonary arteries
– Developing necrotic hemorrhagic nodules or infarcts
– CT:
• Multiple nodules surrounded by a Halo of ground glass
attenuation CT HALO sign or
• Pleural-based wedge-shaped areas of consolidation

50. Halo sign: Angio-Invasive aspergillosis
PA radiograph and axial CT image show right upper lobe mass with
peripheral ground glass opacity constituting Halo sign

51. • Broncho-invasive:
– In patients with severe
neutropenia and in patients
with AIDS
– Chest X-ray: large nodular
opacities to diffuse
parenchymal consolidation

52. Allergic Bronchopulmonary Aspergillosis
(ABPA)
• A hypersensitivity reaction-occurring in major airways
• Associated with asthma, elevated serum IgE levels,
positive precipitins and skin reactivity to aspergillus
• Chest X-ray:
– Non-segmental areas of opacities most common in upper
lobes
– Lobar collapse
– thick tubular opacities due to bronchi distended with
mucus and fungus- Finger-in-gloves sign
– Occasional cavitation

53. Fig. chest x-ray PA view:
branching tubular opacities emanating from the hila -
FINGER-IN-GLOVE appearance

54. • CT:
– Usually, hypodense mucus plugs
– 20% cases- hyperdense mucus plugs
– Branching tubular opacities with high attenuation
– Nearly 30% cases: calcified
– Recurrent attacks:
• Pulmonary fibrosis and bronchiectatic changes

55. Fig. allergic broncho-pulmonary aspergillosis
NECT axial (left) and oblique sagittal (right) chest

56. Fig. allergic bronchopulmonary aspergillosis
HRCT scan demonstrating finger-like opacities due
to dilated mucus-filled bronchi

57. Summary
Fungal pneumonia Specific imaging findings
1 Histoplasmosis • Central, lamellated or diffuse calcification of a nodule
< 3 cm virtually diagnostic
• Acute histoplasma pneumonia: Airspace opacities
any lobe, solitary or multiple; usually lower lungs
• Ipsilateral hilar mediastinal lymphadenopathy
• Fibrosing mediastinitis
2 Coccodioidomycosis Cavitating segmental or lobar consolidation in an
endemic area
Solitary or multifocal segmental or lobar consolidation
Solitary or multiple lung nodules
Mediastinal and hilar nodes
3 Blastomycosis • Airspace disease or mass in an outdoorsman from an
endemic area
• Cavitation

58. Fungal pneumonia Specific imaging findings
4 Paracoccidioidomycosis • Areas of ground glass opacities, interlobular septal
thickening, consolidation, cavitation and fibrosis
5 Candidiasis Chronic pneumonia, abscess, mycetoma formation
Multiple bilateral nodular opacities with areas of
consolidation and ground glass opacities
6 Pneumocystis Peri-hilar ground-glass opacited in a patchy or
geographic distribution with thickened septa

59. Fungal pneumonia Specific imaging findings
7 Cryptococcosis Homogeneous segmental or lobar opacifications
Miliary, reticular or reticulo-nodular interstitial patterns
8 Mucormycosis Lobar or multilobar areas of consolidation
cavitation
9 Aspergillus Aspergilloma of mycetoma formation
Chronic necrotizing aspergillosis
Broncho-invasive with diffuse parenchymal
consolidation
Necrotic nodules surrounded by ground glass
attenuaiton- halo sign
ABPA with non-segmental areas of opacities mainly in
upper lobes, branching thick tubular opacities due to
bronchi distended with mucus- finger-in-glove
appearance

60. Role of the radiologists
• Integrating the clinical data and the radiological
data enables in substantial narrowing of the
differential diagnosis
• Need of guided biopsy in selected cases for
providing a presumptive final diagnosis, especially
when dealing with immuno-compromised patients

61. References
• Text book of Imaging and radiology, David sutton
• Fundamentals of diagnostic radiology, Brant and
Helms
• Grainger and Allison’s Diagnostic radiology
• Christopher M. et al, Imaging Pulmonary Infection:
classic signs and patterns (2014) American journal
of radiology
• Images from Various websites