Histopathological features of human mpox: Report of two cases and review of the literature

Abstract

Human monkeypox is an emerging zoonosis with epidemic potential. Although it usually causes a mild disease, some patients are at risk for complications, including death. In face of the current outbreak of monkeypox in non‐endemic areas, awareness is paramount to diagnose it timely, prompting an early break of the transmission chain. Histopathologic findings in vesiculopustular lesions of monkeypox are distinctive, consisting of ballooning and reticular degeneration of keratinocytes, necrosis, especially of the upper portions of the epithelium, multinucleation of keratinocytes, nuclear enlargement showing a “basophilic halo” around a “ground glass” eosinophilic center, the orthopoxvirus‐specific cytoplasmic eosinophilic Guarnieri‐type inclusions (in the pustular stage especially), and a dense mixed inflammatory cell infiltrate with prominent neutrophil exocytosis. The diagnosis of human monkeypox requires a high index of suspicion. In correlation with clinical information, histopathological findings allow for a presumptive diagnosis of monkeypox if polymerase chain reaction testing is not available. Both clinicians and pathologists can optimize diagnostic sensitivity, respectively, by considering the epidemiological context, sampling pustular lesions and providing data for clinicopathological correlation, and by intentionally searching the tell‐tale eosinophilic inclusions in genital, anal and oral lesions with reticular and ballooning degenerescence.

Clinicopathological and molecular approaches to the diagnosis of oral lesions in Mpox: Case report

“…The most notable histopathological findings, in this case, include early cytopathic changes and the ballooning degeneration of keratinocytes, as described on MPXV skin lesions. 11,16 Although no multinucleated keratinocytes or Guarneri bodies were identified, they have been reported in other case series. 11,16…”

“…11,16 Although no multinucleated keratinocytes or Guarneri bodies were identified, they have been reported in other case series. 11,16…”

“…15 The most notable histopathological findings, in this case, include early cytopathic changes and the ballooning degeneration of keratinocytes, as described on MPXV skin lesions. 11,16 Although no multinucleated keratinocytes or Guarneri bodies were identified, they have been reported in other case series. 11,16 The confirmation of the MPXV infection was achieved through RT-PCR from a skin lesion sample, which is considered the gold standard for the diagnosis of MPXV infection.…”

“…11,16 Although no multinucleated keratinocytes or Guarneri bodies were identified, they have been reported in other case series. 11,16 The confirmation of the MPXV infection was achieved through RT-PCR from a skin lesion sample, which is considered the gold standard for the diagnosis of MPXV infection. 17 Additionally, electron microscopy analysis provided further insights into the ultrastructural characteristics of MPXV infection, contributing to our understanding of the pathological oral changes induced by MPXV.…”

A Narrative Review on the Monkeypox Virus: An Ongoing Global Outbreak Hitting the Non-Endemic Countries

“…These samples require room temperature, but no media for transportation, except for tissue biopsies, which require transportation in a frozen state on dry ice. Histopathology findings show ballooning and multinucleation of keratinocytes with full-thickness epidermal necrosis, nuclear enlargement with an eosinophilic center and basophilic halo, and orthopoxvirus-specific eosinophilic cytoplasmic inclusions, called "Guarnieri bodies" or "B-type inclusions" [ 34 - 35 ]. Immunohistochemistry can also identify antigens on biopsies, while the modality of PCR can even differentiate between the two monkeypox clades.…”