A Retrospective Analysis of Pigmented Basal Cell Carcinoma in a Tertiary Care Center.

Sir,

Pigmented basal cell carcinoma (pBCC) is distinct clinically and histologically, which accounts for 6% of total basal cell carcinoma (BCC).[12] Though rare, it is becoming more common among the Asian population secondary to increased tropical ultraviolet exposure. In this study, we report our retrospective analysis of pBCC occurring in the skin color of patients encountered in our tertiary care center.

Epidemiological data were retrospectively collected from the registry, which was analyzed and statistically evaluated. The 10 pBCC patients comprised of three males and seven females. The mean age was 59 ± 11.78 years (range: 40–76 years). Most of our patients were in the sixth decade while presenting to us. The mean duration of the patient noticing the skin lesion and seeking medical care was 21 ± 12.52 months (range: 6–36 months). All our patients belonged to Fitzpatrick phototype V. Occupational sun exposure was a major risk factor among all our patients with a mean sun exposure of 5 ± 1.37 hours per day (range 2–8 hours). None of them had undergone any Psoralen Ultraviolet A (PUVA) therapy or any known exposure to metals or chemicals in the past. There was no family history of cutaneous malignancy in our patients. All our patients had pBCC over their face with the nose being the most common site (40%), followed by the forehead (30%). Six patients had a solitary lesion while four presented with multiple lesions (range: 2–4). Five of our patients presented with ulceration, with a mean duration of 30 ± 7.5 months (range: 18–36 months). Patients without ulceration had a mean duration of 11 ± 8.04 months (range: 3–24 months). Thus, ulceration is more common among people with a prolonged duration of the disease. The pigmentation of the tumor was mostly dispersed over the periphery in six patients [Figure 1]. Five of our patients underwent surgery with reconstruction, and three patients did not follow up. The patients who were treated did not have any metastasis or fatal outcome.

Figure 1

(1) Irregular black and blotchy crusted multinodular plaque of 3x3 cms over the left postauricular region, (2) Hyperpigmented arcuate plaque of 2x1 cms, with central atrophy over the right side of forehead, (3) Hyperpigmented plaque of 3x1 cms, with a central ulcer over right infraorbital region, (4) Well-defined bluish-black plaque of 2x2 cms, with rolled out margins over the chin, (5) Hyperpigmented arcuate plaques, largest measuring 3x2 cms, with central atrophy over the forehead, (6) Oval-shaped hyperpigmented ulcerated plaque of 5x3 cms over the right retro-auricular region, (7) Well-defined bluish-grey annular plaque of 2x1 cms with areas of atrophy over the nose, (8) Bluish-grey scaly crusted plaque of 2x2 cms, with secondary ulceration over the nose, (9) Well-defined bluish-black plaque of 2x2 cms, with ulceration over the nose, (10) Black to bluish-grey hyperpigmented crusted plaques, largest measuring 3x2 cms, with erosion over the nose and forehead

The color of pBCC is attributed to the increased number of melanocytes and melanin production. The high dermal pigmentation at the borders marks the tumor margin. Clinically, pBCC presents as papules or nodules with color varying from blue, tan, brown, black over a part or throughout the lesion. A deeper inspection reveals the elevated, pearly white translucent border distinctive to BCC. Ulceration may be present in a few. The subclinical infiltration is less compared to other variants and hence it has a better prognosis.[134] The pBCC mimics are melanoma, pigmented Bowen’s disease, and melanoacanthoma. The diagnosis can be confirmed using invasive methods like incisional and excisional biopsy or non-invasive methods like dermoscopy, spectrophotometric intracutaneous analysis scope, and reflectance confocal microscopy. The histopathological examination is the confirmatory diagnostic approach. It has predominant basaloid cell islands with peripheral palisading, cleft artifact between the epithelium and the stroma, with increased melanin, melanophages, and moderate inflammatory infiltrates [Figure 2a and b]. The melanophages are maximally seen in the stroma. The large tumor melanocytes with numerous dendrites are located along the basal layer and also interspersed between the tumor cells along the centre of the tumor nest.[12] Fontana–Masson stain detects melanin in the tumor [Figure 2c]. Further immunohistochemistry study reveals MELAN-A (MART-1), HMB-45, and MiTF positivity. The criteria for dermoscopic findings (sensitivity of 93% and a specificity of 89%) are as follows: Absent pigment network in addition to any one of the following, like ulceration, large blue-gray ovoid nests, multiple blue-gray globules, maple leaf-like areas, spoke wheel areas, or arborizing telangiectasias.[5] In our cases, dermoscopy was not very much contributory because of the intense pigmentation, resulting in an inability to visualize the other components of classical BCC [Figure 3]. Surgical treatment remains the first line of approach and Mohs’ surgery is the most effective method. There was no recurrence noted, compared with 20% of the non-pigmented variants. Electric cauterization, curettage techniques, and cryotherapy are other destructive modalities used. Other options include 5-Fluorouracil, imiquimod, intralesional interferon-alpha, photodynamic therapy, and LASER therapy.[6]

Figure 2

(a and b) Islands, sheets and cords of basaloid tumor cells with peripheral palisading and cleft formation (retraction artefact). Tumor shows focal deposits of melanin and scattered melanophages in the surrounding stroma. Tumor cells have uniform hyperchromatic nuclei and scant cytoplasm (H and E stain, (a) 10× and (b) 40×. (c) Fontana-Masson stain highlights melanin (40× magnification)

Figure 3

Large blue-gray ovoid nests (blue circle) and multiple brown globules/clods (blue arrow), ulceration (yellow circle), arborizing vessel (yellow arrow), maple leaf like areas (red circle) and shiny white lines/chrysalids (red arrow). (Image taken with Dermlite D4 dermoscope, 10× magnification, polarized image)

Thus, a high index of suspicion is needed to diagnose pBCC as it mimics a few other pigmented dermatological conditions. Increased awareness can help in the early diagnosis, and hence better treatment outcomes, especially among the susceptible oncologic population.

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Conflicts of interest

There are no conflicts of interest.