Clinical, histopathologic, immunohistochemical, and electron microscopic findings in cutaneous monkeypox: A multicenter retrospective case series in Spain.

BACKGROUND: The worldwide outbreak of monkeypox has evidenced the usefulness of the dermatologic manifestations for its diagnosis. OBJECTIVE: To describe the histopathologic and immunohistochemical findings of monkeypox cutaneous lesions. METHODS: This is a retrospective histopathologic and immunohistochemical study of 20 patients with positive Monkeypox virus DNA polymerase chain reaction and immunohistochemical positivity for Vaccinia virus in cutaneous lesions. Four cases were also examined by electron microscopy. RESULTS: The most characteristic histopathologic findings consisted of full-thickness epidermal necrosis with hyperplasia and keratinocytic ballooning at the edges. In some cases, the outer root sheath of the hair follicle and the sebaceous gland epithelium were affected. Intraepithelial cytoplasmic inclusion bodies and scattered multinucleated keratinocytes were occasionally found. Immunohistochemically, strong positivity with anti-Vaccinia virus antibody was seen in the cytoplasm of ballooned keratinocytes. Electron microscopy study demonstrated numerous viral particles of monkeypox in affected keratinocytes. LIMITATIONS: Small sample size. Electron microscopic study was only performed in 4 cases. CONCLUSION: Epidermal necrosis and keratinocytic ballooning are the most constant histopathologic findings. Immunohistochemical positivity for Vaccinia virus was mostly detected in the cytoplasm of the ballooned keratinocytes. These findings support the usefulness of histopathologic and immunohistochemical studies of cutaneous lesions for diagnosis of monkeypox.

Vasculogenic mimicry-associated ultrastructural findings in human and canine inflammatory breast cancer cell lines.

BACKGROUND: Human inflammatory breast cancer (IBC) and canine inflammatory mammary cancer (IMC) are the most lethal mammary cancers. An exacerbated angiogenesis and the existence of vasculogenic mimicry (VM) are hallmarks of these tumors. The information regarding VM and ultrastructural characteristics of mammary cell lines is scant. METHODS: In this study, IBC cell line SUM149 and IMC cell line IPC-366 in adherent (2D) and non-adherent (3D) (mammospheres, cancer stem cells) conditions were analyzed by transmission and scanning electron microscopy (TEM and SEM, respectively). RESULTS: The TEM revealed round to oval shape cells with microvilli on the surface, high numbers of peroxisomes in close apposition to lipid droplets and some extracellular derived vesicles. The TEM and the SEM mammospheres revealed group of cells clumping together with a central lumen (resembling a mammary acini). The cells joint are tight junctions and zonula adherens. By SEM two cell morphologies were observed: spherical and flattened cells. There was evidence endothelial-like cells (ELCs), which is characteristic for this disease, showing several or unique cytoplasmic empty space. ELCs were more frequent in 3D than in 2D culture conditions and contained Weibel-Palade cytoplasmic bodies, which are exclusive structures of endothelial cells. CONCLUSIONS: Both cell lines, IPC-366 and SUM-149, shared ultrastructural characteristics, further supporting canine IMC as a model for the human disease. To the best of our knowledge, this is the first study that demonstrate the morphological differentiation of cultured cancer stem cells from cancer epithelial cell lines into endothelial-like cells, confirming the vasculogenic mimicry phenomenon from an ultrastructural point of view.