Dotted Vessels in a Reticular Arrangement.

Case presentation

We report a case of a 56-year-old male patient who presented for evaluation of a tumor on his right lower back ( Figure 1A). He reported that he observed the lesion for the first time 3 years earlier and, since then, it gradually increased in size and was sporadically traumatized.

Figure 1

(A) Nodular and pink skin lesion measuring 23 mm on patient right lower back. (B) Glomerular and dotted vessels with a reticular arrangement at the periphery of the lesion (white circles), linear mixed and hairpin-like vessels (white arrows irregularly distributed in the center and eccentrically. White structureless areas were also focally present.

Dermoscopy revealed glomerular and dotted vessels with a reticular arrangement at the periphery of the lesion (white circles, Figure 1B), but also linear mixed and hairpin-like vessels (white arrows, Figure 1B) irregularly distributed in the center and eccentrically. White structureless areas were also focally present (Figure 1B).

Although reticularly arranged dotted vessels are suggestive of a clear cell acanthoma (CCA) (1), the uneven distribution of vessels in the lesion and the co-existence of other morphologic vessel types did not allow a confident clinical diagnosis. Therefore, the lesion was excised with a clinical differential diagnosis including CCA, non-pigmented eccrine poroma (2), amelanotic melanoma and poorly differentiated squamous cell carcinoma.

Histopathology confirmed the diagnosis of CCA.

Teaching Point

Dotted vessels in a reticular arrangement (“string of pearls” in the metaphoric terminology) are strongly indicative of CCA.

However, excisional biopsy and histopathological examination is mandatory for any nodular lesions that will express only in part the dermoscopic criteria for clear cell acanthoma.