PMC4899652_01
a A red-colored, elastic, soft, well-demarcated nodule on the left cheek. b The tumor spontaneously regressed 20 days after the biopsy.
cde-0008-0052-g01.jpg
PMC4899652_01_cde-0008-0052-g01.jpg
F1
On her initial visit, physical examination revealed a red-colored, elastic, soft, well-demarcated nodule on her left cheek (fig. 1a). Surprisingly, the tumor spontaneously regressed 20 days after the biopsy (fig. 1b).
a Sheets of small cells with hyperchromatic nuclei extending throughout the dermis with prominent leukocytes. b Paraffin-embedded tissue samples were deparaffinized and stained with anti-synaptophysin antibodies. The sections were developed with 3,3'-diaminobenzidine tetrahydrochloride (original magnification x100).
cde-0008-0052-g02.jpg
PMC4899652_01_cde-0008-0052-g02.jpg
F2
A biopsy specimen from her cheek revealed sheets of small cells with hyperchromatic nuclei extending throughout the dermis with prominent leukocytes (fig. 2a). Immunohistochemical staining revealed that these atypical cells were positive for CK20, synaptophysin (fig. 2b) and neuron-specific enolase, and negative for chromogranin A, thyroid transcription factor 1, S-100, Melan-A and HMB-45.
Paraffin-embedded tissue samples were deparaffinized and stained with anti-CD8 antibodies (a), anti-granulysin antibodies (b), and anti-caspase 3 antibodies (c). The sections were developed with Liquid Permanent Red (original magnification x100).
cde-0008-0052-g03.jpg
PMC4899652_01_cde-0008-0052-g03.jpg
F3
To further investigate the possible mechanisms in the spontaneous regression, we employed immunohistochemical staining of CD8 (fig. 3a), CD163, CD206, Foxp3, granulysin (fig. 3b) and caspase 3 (fig. 3c) for the present case and 5 cases of conventional MCC.
Summary of the average number of immunoreactive cells in the 5 conventional MCC cases and the present case. Three representative fields of each section were selected from tumor areas with dense dermal lymphoid infiltrates. The number of immunoreactive cells was counted using an ocular grid of 1 cm2 at a magnification of x400. The data are expressed as the means +- SD of the numbers in each area. White bars: conventional MCC; black bars: present case.
cde-0008-0052-g04.jpg
PMC4899652_01_cde-0008-0052-g04.jpg
F4
In the present case, the number of CD8+ cells, granulysin-bearing cells and caspase 3+ cells tended to be higher than in conventional MCC cases (fig. 4).