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Cryptococcal inflammatory pseudotumors
Yetish Sing1, Pratistadevi K Ramdial
1Department of Anatomical Pathology, Nelson R Mandela School of Medicine, University of KwaZulu Natal and National Health Laboratory Service, Durban, KwaZulu Natal, South Africa.
Abstract:
"Inflammatory pseudotumors" (IPTs) embrace a heterogeneous spectrum of reactive, infective, and neoplastic entities, that are characterized by a clinical mass composed of a histologic proliferation of spindle cells in a background of inflammatory cells and collagen fibers. Although a spectrum of microorganisms have been identified in infective IPTs, mycobacterial infective IPTs are reported most commonly. We document 5 solitary cryptococcal IPTs, in 2 males and 3 females, aged 19 to 43 years, in the soft tissues of the anterior chest wall, thigh, and arm. All were HIV-positive and had been treated for disseminated cutaneous and/or meningeal cryptococcosis with antifungal therapy, 6 to 12 months earlier. The specimens demonstrated a storiform arrangement of plump spindle cells, in addition to spindle and polygonal cells that were arranged in a haphazard manner. Background lymphocytes, plasma cells, and fibrosis were noted, in addition to scattered giant cells and focal necrosis. On high-power examination, Cryptococcus neoformans yeasts were identified within and between vacuolated spindle and polygonal cells on routine and special stains, confirming cryptococcal IPTs. Immunophenotyping of the spindle cells confirmed a mixed histiocytic and myofibroblastic lineage, with a predominance of the former. In documenting 5, hitherto unreported, pseudotumoral spindle cell reactions to C. neoformans, we not only highlight the need for intense appraisal of all IPTs for infective agents on routine and special stains and investigations, but also postulate that a complex host-fungus interaction, coupled with an exuberant, myofibroblastic response to incomplete therapy, are the pathogenetic drive for the pseudotumoral presentation.
Insights
This study identifies five cases of cryptococcal inflammatory pseudotumors (IPTs) in HIV-positive patients. These rare fungal masses highlight the need to investigate IPTs for infectious agents like Cryptococcus neoformans.
Area of Science:
- Pathology
- Mycology
- Infectious Diseases
Background:
- Inflammatory pseudotumors (IPTs) are a diverse group of conditions presenting as a mass with spindle cell proliferation and inflammation.
- While various microorganisms can cause infective IPTs, mycobacterial infections are most frequently reported.
- Cryptococcal infections, particularly in immunocompromised individuals, can manifest in unusual ways beyond typical presentations.
Purpose of the Study:
- To document and characterize previously unreported cases of solitary cryptococcal inflammatory pseudotumors (IPTs).
- To investigate the immunophenotype of spindle cells within these lesions.
- To explore the potential pathogenetic mechanisms driving pseudotumoral reactions to Cryptococcus neoformans.
Main Methods:
- Retrospective analysis of five patient cases diagnosed with solitary cryptococcal IPTs.
- Histopathological examination of tissue specimens, including routine and special stains, to identify Cryptococcus neoformans.
- Immunophenotyping of spindle cells to determine their lineage (histiocytic, myofibroblastic).
Main Results:
- Five cases of solitary cryptococcal IPTs were identified in the soft tissues of HIV-positive patients previously treated for disseminated cryptococcosis.
- Histology revealed spindle cell proliferation with inflammatory background, lymphocytes, plasma cells, fibrosis, giant cells, and necrosis.
- Cryptococcus neoformans yeasts were confirmed within vacuolated spindle and polygonal cells; immunophenotyping showed a mixed histiocytic and myofibroblastic lineage.
Conclusions:
- This study reports the first five cases of pseudotumoral spindle cell reactions to Cryptococcus neoformans, termed cryptococcal IPTs.
- It emphasizes the critical need for thorough investigation of all IPTs for infectious etiologies using appropriate stains and diagnostic methods.
- A complex interplay between the host's immune response, the fungus, and potentially incomplete antifungal therapy may drive this pseudotumoral presentation.
