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Letter

Black and Pink: Single Lesion or Double Diagnosis?

Author Affiliation(s)

Introduction

Fibroepithelioma of Pinkus (FeP) is an uncommon skin lesion considered to be a rare variant of basal cell carcinoma (BCC), even though some researchers have argued for its classification as a trichoblastoma. FeP appears frequently as a solitary, flesh-colored, well-demarcated plaque, typically localized on the lumbosacral area of patients aged 40 to 60 years. It often develops in patients with a history of BCC, most commonly in women [ 1 ] .

Dermoscopy of FeP is characterized by the presence of long, linear, irregularly distributed telangiectasia; whitish striations that sometimes cover larger areas or form a honeycomb pattern, indicating a highly collagenized or fibrotic stroma; brownish gray unstructured pigmentation; punctate vessels; milia-like cysts and follicular keratotic plugs.

The differential diagnoses include dermal melanocytic nevus, pedunculated fibroma, acrochordon, and seborrheic keratosis. The recommended treatment of FeP is complete excision. Its clinical behavior is not aggressive and, because of its good prognosis, no special follow-up is recommended [ 1 ] .

Case Presentation

A 71-year-old white man presented to our outpatient dermatology clinic for a routine skin examination. He had a history of 2 completely excised BCCs on the face. Examination revealed diffuse actinic damage on sun-exposed skin areas. We noticed an atypical lesion on the lumbar back of irregular shape, approximately 0.8 cm in diameter and slightly raised ( Figure 1 ). The lesion presented a pigmented area and a distinct pink area. Dermoscopic characteristics included, on the pigmented area, hyperpigmented blotches, blurred borders, and irregular peripheral network. Nonpigmented area findings included pink color, dotted and polymorphous vessels, fine white scales, white septal streaks, and a focal ulceration area.

Figure 1 .

Dermoscopic characteristics of the pigmented area: hyperpigmented blotches, blurred borders, and irregular peripheral network. Nonpigmented area findings: pink color, dotted and polymorphous vessels, fine white scales, white septal streaks, and a focal ulceration area.

Histological examination revealed a proliferation of basaloid cells, with hyperchromatic nuclei and central mature keratinization, in part confined to the epidermis, in part composed of anastomosing strands emanating downward from the epidermis in the context of fibromyxoid stroma. Adjacent to this area, a proliferation of mature melanocytes distributed in single cells and rare nests was observed along the dermoepidermal junction, with dermal fibrosis and abundant lymphocytic infiltrate. The 2 proliferations were located less than 0.1 mm from one another ( Figure 2 ).

Figure 2 .

(A) Low-power photomicrograph showing skin with a proliferation of basaloid cells and a melanocytic proliferation along the dermoepidermal junction, with dermal fibrosis and abundant lymphocytic infiltrate. The 2 proliferations were located less than 0.1 mm from one another (magnification ×2). (B) High-power photomicrograph showing the basaloid lesion composed of anastomosing basaloid strands emanating downward from the epidermis in the context of fibromyxoid stroma (magnification ×20). (C) High-power photomicrograph showing proliferation of melanocytes distributed in single cells and rare nests along the dermoepidermal junction (magnification ×20).

Histological diagnosis: “keratotic variant of superficial basal cell carcinoma with focal features of fibroepithelioma of Pinkus. The lesion collides with a melanocytic junctional nevus with regression areas.”

Conclusions

In this case, a BCC with focal FeP aspects collided with a junctional melanocytic nevus with regression areas. Dermoscopy of this lesion differed from the classic FeP description, even though typical BCC patterns were not so evident. In our opinion, at a first dermoscopic look, the lesion could be misdiagnosed as a superficial spreading melanoma with a nodular component because the pink area could resemble melanoma regression and nodulation.

We believe that our case is of particular interest also because, to our knowledge, the collision between FeP and melanocytic proliferation has been previously described only once, by Sunassee et al [ 2 ] .

References

  1. Fibroepithelioma of Pinkus revisited Haddock ES, Cohen PR. Dermatol Ther (Heidelb).2016;6(3):347-362.
  2. Combined melanocytic nevus, superficial congenital and deep penetrating types with fibroepithelioma of Pinkus, collision tumor—a case report Sunassee A, Kerkvliet AM, Jassim AD. S D Med.2017;70(8):363-365.

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