Autopsy findings in 51 year-old man with mantle cell lymphoma Bobbi S. Pritt, MD, MSc Professor of Laboratory Medicine and Pathology Mayo Clinic Disclosure of Relevant Financial Relationships USCAP requires that all faculty in a position to influence or control the content of CME disclose any relevant financial relationship WITH COMMERCIAL INTERESTS which they or their spouse/partner have, or have had, within the past 12 months, which relates to the content of this educational activity and creates a conflict of interest. Dr. Bobbi Pritt declares she has no conflicts of interest to disclose. A 51 year old man with end-stage mantle cell lymphoma, refractory to treatment Patient expired due to acute hemorrhagic bronchopneumonia involving all lung lobes. Autopsy revealed bacterial pneumonia; post-mortem cultures grew multiple bacteria and Candida albicans Cause of death: bacterial pneumonia complicating mantle cell lymphoma Neuropath exam: Recent multifocal hemorrhagic lesions Subarachnoid hemorrhages Intraparenchymal hemorrhage with associated parenchymal necrosis Subarachnoid hemorrhage overlying the left inferior temporal lobe, left parietal and occipital lobes 1
Intra-parenchymal hemorrhages with associated necrosis of left basal ganglia, left parietal lobes and right occipital lobe. H&E, 20x total magnification (2x objective) Basal ganglia lesion H&E, 200x basal ganglia lesion showing hemorrhage and necrosis; no organisms seen. H&E, 20x meninges overlying hemorrhagic basal ganglia lesion H&E, 100x H&E, 200x 2
GMS, 100x GMS, 400x 5 to 20 micrometers in diameter Identification? A. Candida albicans B. Coccidioides immitis C. Cryptococcus neoformans D. Corpora amylacea E. Chrysosporium zonatum Final neuropath diagnosis in this case Recent multifocal hemorrhagic lesions with no identifiable infection or viable lymphoma cells Yeasts in Tissue My approach 3
Ask: given the morphologic appearance, which yeasts are in your differential? (in this case, 5 to 20 micrometers in diameter) Algorithm for identifying yeasts in tissue Small (2-7 µm) Oval Round H. capsulatum most likely Narrow-based budding, not easily visible (eosinophilic) by H&E with pseudocapsule Also consider C. glabrata Identical appearance to H. capsulatum on GMS, BUT visible (basophilic) by H&E Also Consider: Other Candida spp. (larger, 3-6 µm, pseudohyphae, hyphae) Malassezia spp. (very small, 2-3 µm broad-based budding) Sporothrix schenckii (elongated forms) Begin with Morphologic Assessment on H&E and GMS Variable size (2-20 µm) Small and large forms Budding Present? C. neoformans/gattii most likely Thin cell wall, often collapsed forms, halo on H&E and GMS where capsule is present, narrowbased budding, occasional pseudohyphae Also Consider: Coccidioides most likely - look for evidence of spherules Large (8-15 µm) Budding Present? Narrow based Broad based B. dermatitidis most likely Thick double-contour cell wall, uniform size, may see occasional small forms Penicillium marneffei (transverse septations, patient from SE Asia) Pneumocystis jiroveci (intra-alveolar, intra-cystic body, immunocompromised pt.) Paracoccidioides brasiliensis (smaller multiple buds around parent cell) Algorithm for identifying yeasts in tissue Begin with Morphologic Assessment on H&E and GMS Algorithm for identifying yeasts in tissue Begin with Morphologic Assessment on H&E and GMS Small (2-7 µm) Variable size (2-20 µm) Large (8-15 µm) Small (2-7 µm) Variable size (2-20 µm) Large (8-15 µm) Small and large forms Small and large forms Budding Present? Coccidioides spp. most likely - look for evidence of spherules C. neoformans/gattii most likely Thin cell wall, often collapsed forms, halo on H&E and GMS where capsule is present, narrow-based budding, occasional pseudohyphae Also Consider: Paracoccidioides brasiliensis Main differential: Cryptococcus spp. or Coccidioides spp. (smaller multiple buds around parent cell) Smooth outer contour on GMS/PAS Smooth outer contour on GMS/PAS Consistent appearance on H&E Our case 4
Smooth outer contour on GMS/PAS Consistent appearance on H&E Evidence of budding/other structures Corpora amylacea Cryptococcus neoformans C. neoformans/c. gattii narrow-based budding Our case B. dermatitidis broad-based budding Smooth outer contour on GMS/PAS Consistent appearance on H&E Evidence of budding/other structures Knowledge of common mimics is also helpful Corpora amylacea Step 2: Identifying the mimics Variably-sized eosinophilic to basophilic bodies Found in the prostate, brain, lung Composed of amyloid and glycoproteins Laminated appearance, 5 to 200 µm diameter May contain calcium, but not usually lipid or iron Often GMS and PAS positive Different proposed mechanisms of formation in different organs: Brain found within astrocyte cytoplasm, subpial and perivascular locations Common in aging brain Increased numbers in neurodegenerative conditions 5
Other fungal mimics Numerous! Calcified bodies associated with necrosis or degenerated tissue (dystrophic calcification) Irregular contours, sizes Stain positive with: Calcium stains (Alizarin red, Azan) Von Kossa (phosphate, carbonate) Usually GMS negative Other fungal mimics, continued Gamna-Gandy Bodies Variably-sized clear to yellow-brown objects with irregular contours Composed of dense collagen and elastin fibers encrusted with calcium and iron Often seen in areas of hemorrhage, especially spleen (up to 12% of patients with portal hypertension and congestive splenomegaly) Stain with: Iron stains (e.g. Prussian blue) May be PAS positive Usually not GMS positive Other fungal mimics, continued Hamazaki-Wesenberg bodies Small round-oval ceroid bodies Found in lymph node sinuses Found in up to 70% of mesenteric lymph nodes at autopsy medical significance GMS, PAS and Fontana-Masson + Brown on H&E Other fungal mimics, continued Liesegang rings Myospherulosis Foreign bodies (e.g. plant material) Over-stained host cells (WBCs, RBCs, collagen fibers) Environmental fungal contaminants 6
A final case Brain biopsy from a 60-yearold man with a large ringenhancing lesion Tissue shows mostly necrosis PAS stain was performed as part of the ID pathology workup Diagnosis? Blood vessels 7
Main points from these cases There are a number of fungal mimics Knowing their names can make you sound smart! But it s more important to recognize that they are mimics and not actual microorganisms even if you can t say what they are exactly. In general, mimics show: More variability in size and shape true budding or other forms Irregular, fragmented forms Unexpected stain reactions Lack of associated host immune response Familiarity with commonly-seen mimics aids in differentiating them from true microorganisms. Questions? 8