Calcified Pilocytic Astrocytomas and Calcifying Pseudoneoplasms of the Neuraxis: A Diagnostic Challenge

Rebeca Hernández-Reséndiz ¹, Eliezer Villanueva-Castro ², Edgardo de Jesus Mateo-Nouel ²

⁰Department of Pediatric Neurology, Hospital Angeles Universidad, Mexico City, MEX.

Cureus +

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February 7, 2024

View abstract on PubMed

Summary

Pilocytic astrocytoma with calcifications may represent calcifying pseudoneoplasms of the neuraxis (CAPNON), challenging traditional classifications. This finding suggests new diagnostic and therapeutic approaches for these central nervous system tumors.

Area Of Science

Neuro-oncology
Pathology
Immunohistochemistry

Background

Pilocytic astrocytoma (PA) is the most common central nervous system (CNS) tumor, often exhibiting calcifications.
Calcifications in PA are typically associated with benign or indolent growth patterns.

Purpose Of The Study

To investigate the calcified attributes of pilocytic astrocytoma (PA) with calcifications and psammoma bodies (PB).
To explore potential reclassification of these tumors, possibly as calcifying pseudoneoplasms of the neuraxis (CAPNON).

Main Methods

Retrospective analysis of seven histopathologically diagnosed cases of pilocytic astrocytoma with calcifications and psammoma bodies.
Histological examination and immunohistochemical analysis, including glial fibrillary acidic protein (GFAP), vimentin, osteopontin, epidermal growth factor receptors (EGFR), tumor necrosis factor-alpha (TNF-α), and interleukin 1 beta (IL-1β).

Main Results

Calcifications showed positive reactivity for GFAP, osteoconduction, and osteopontin.
Hyaline bodies exhibited an atypical immune profile: negative for vimentin and GFAP, but positive for EGFR, TNF-α, and IL-1β.
Recurrence in four cases despite overall survival, questioning the conventional PA classification.

Conclusions

The atypical immune profile and recurrence patterns suggest that some calcified pilocytic astrocytomas may actually be calcifying pseudoneoplasms of the neuraxis (CAPNON).
This study highlights the complex interplay between PA and CAPNON, necessitating a re-evaluation of diagnostic criteria.
Findings may lead to novel diagnostic and therapeutic strategies in neuro-oncology for these challenging tumors.

Keywords:

calcified pilocytic astrocytoma calcifying pseudoneoplasm of the neuraxis capnon dystrophic calcification glioma psammoma bodies senescence-associated secretory phenotype tumor calcifications tumor markers