A 9-year-old girl is brought to the physician by her parents because she has been scratching a group of small bumps on the skin of her forearm for the past month. On physical examination, there are five 0.4- to 0.9-cm, small, flat to slightly papular, pale brown lesions on the volar surface. The lesions become more pruritic with swelling and erythema when rubbed. A biopsy specimen of one of the lesions examined microscopically shows an upper dermal infiltrate of large cells with abundant pink cytoplasm that stains an intense purple color with toluidine blue. Which of the following cell types is most likely to form these lesions?
□ (A) CD4+ lymphocyte
□ (B) CD8+ lymphocyte
□ (C) Langerhans cell
□ (D) Macrophage
□ (E) Mast cell
□ (F) Melanocyte
□ (G) Merkel cell
