Pigmented follicular cyst pathology

This benign lesion is grouped within the cutaneous cysts

Histology of pigmented follicular cyst

Scanning power view demonstrates a unilocular cystic structure within the dermis (Figure 1). Higher power reveals a thin epithelial lining with a retained granular layer (Figures 2 and 3). Within the cyst cavity are loose keratin fragments and numerous pigmented terminal hair shafts (Figures 2 and 3).

Figure 1 

Figure 2 

Figure 3 

Differential diagnosis of pigmented follicular cyst

Vellous hair cyst: In this lesion the cyst cavity contains small vellous hairs lacking pigmentation.

Epidermal inclusion cyst: Hair fragments are absent.