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Basal cell carcinoma (BCC) is the most frequent skin neoplasm, and generally occurs on sun-exposed, hair-bearing areas, especially on the face. Cumulative sun exposure is thought to be integral to lesion formation. BCC on the palm or sole is extremely rare, because both sites are glabrous and neoplastic cells of BCC differentiate towards follicular germinative cells.1 Dermoscopy has been considered as a valuable tool for diagnosing skin tumors including BCC. Although Ikumi et al.2 have reported dermoscopic findings of BCC on glabrous skin in their published work, there is no dermoscopic photo. We herein report a case of BCC arising on the palm and its dermoscopic findings. We also reviewed the published work on BCC of the palm and sole.

A 76-year-old woman visited the outpatient clinic of the Department of Dermatology of Tokushima University Hospital, complaining of a keratotic plaque on the left palm that had been present for 5 years. A 15 mm × 17 mm, slightly elevated, skin-colored plaque with a keratotic, crusted center was seen on the lateral aspect of the left thenar (Fig. 1a). The lesion was asymptomatic, and there was no pit on her palm or sole. No history of trauma, burn or irradiation at the site of the lesion or jaw cyst was noted.

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Figure 1.  Tumor on the lateral aspect of the left thenar showed a keratotic center with crust and surrounding skin-colored elevation (a). Dermoscopic findings reveal dotted vessels (red arrowheads) and large, blue-gray, ovoid nests (violet arrows) at the periphery of the lesion. Ulcerations (green arrows) were also observed (b). Aggregations of basaloid cells with peripheral palisading, continuous with the undersurface of the epidermis (c). Clefts with mucin deposition between cell nests and adjacent, altered stroma (d). Tumor cells contained a few melanin pigments in the cytoplasm (c,d: hematoxylin–eosin)

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On dermoscopic examination, dotted vessels and several large, blue-gray, ovoid nests were seen at the periphery of the lesion. Leaf-like structures, wheel spoke areas and ulceration were also observed (Fig. 1b). However, neither arborizing vessels nor pigment network were recognized.

Histopathological examination of a biopsy specimen taken from the center of the tumor revealed aggregations of basaloid cells continuous with the undersurface of the epidermis (Fig. 1c). Neoplastic cells had small, ovoid, monomorphous nuclei and scant cytoplasm. Cells at the periphery of aggregations were columnar and arranged in a palisade fashion, and clefts with mucin deposition were observed between aggregations and adjacent altered stroma (Fig. 1d). Some tumor cells contained melanin pigment in the cytoplasm. From these findings, a diagnosis of superficial type BCC was made. The lesion was excised with a 5-mm margin. Histopathological findings of the excised specimen were similar to those of the biopsy specimen. No recurrence was noted 7 months after resection.

Immunohistological examinations using antibodies to estrogen, progesterone and androgen receptors (all from Takara, Shiga, Japan) revealed that neoplastic cells did not exhibit any of these sex hormone receptors.

Basal cell carcinoma on glabrous skin is often observed in patients with nevoid basal cell carcinoma syndrome (NBCCS). BCC on the palm is extremely rare in patients without NBCCS. To our knowledge, only 12 cases have been reported in the English-language published work3–14 and eight other cases, including the present case, in the Japanese published work.2 Clinical data on those cases are summarized in Table 1. Nine out of the 12 cases in the English-language published work and seven out of the eight cases in the Japanese involved women. All 12 cases in the English-language published work and seven out of the eight Japanese cases were solitary lesions. Four cases in the English-language and two in the Japanese published work had a history of triggering factors such as trauma,2,8,13,14 scar6 or irradiation2 at the site of the lesion.

Table 1.    Summary of the reported cases of palmar basal cell carcinoma in the Japanese and English-language published work
 AuthorsAge (years)SexRemarks
  1. n.d., not described.

 1Johnson et al.370MSolitary
 2Hyman et al.450FSolitary
 3Santa-Cruz et al.550MSolitary
 4Robins et al.655FSolitary, scars of blister (epidermolysis bullosa dystrophica)
 5Rupec et al.7n.d.n.d.Solitary
 6Starzycki et al.860FSolitary, traumatic wound
 7Schnall et al.940FSolitary
 8Piro et al.1062FSolitary
 9Salomão et al.1149FSolitary
10Park et al.1274FSolitary
11Lateo et al.1373FSolitary, trauma
12Abeldaño et al.1464FSolitary, trauma
13Okumura et al.250MMultiple, radiation
14Oji et al.228FSolitary
15Akamatsu et al.257FSolitary
16Naruse et al.261FSolitary
17Iki et al.256FSolitary
18Suzuki et al.278FSolitary, trauma
19Ikumi et al.267FSolitary
20Present case76FSolitary

Roth et al.15 reported 20 cases of BCC of the sole, and identified similar biological characteristics to the palm. Fifteen of these 20 cases involved women, and all showed solitary lesions. Only three cases arose from the scar. Alcalay et al.16 reviewed 20 cases of BCC of the sole reported in the published work, and also found a female predominance (16/20). The reason for the female predominance in BCC on glabrous skin is unclear, so we conducted immunohistochemical staining of sex hormone receptors to analyze the involvement of sex hormones in BCC of the palm. However, androgen, estrogen and progesterone receptors were all negative in neoplastic cells in our case. Therefore, sex hormones did not have an influence on the development of BCC on the palm.

Recently, dermoscopic examination has been recognized as a valuable tool in diagnosing some skin tumors, especially pigmented ones. Although Ikumi et al.2 have reported dermoscopic findings of BCC on glabrous skin in their published work, there is no dermoscopic photo. We recognized dotted vessels, blue-gray ovoid nests, leaf-like structures, wheel spoke areas and ulceration, all of which are characteristic features in common BCC, but no arborizing vessels. However, because it is unclear whether these results are specific to BCC of glabrous skin, we should accumulate dermoscopic findings in more such cases.

Acknowledgment

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  2. Acknowledgment
  3. References

We thank Dr Masaru Tanaka, Professor of Tokyo Women’s Medical University Medical Center East, for his valuable advice on dermoscopic findings of this case.

References

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  2. Acknowledgment
  3. References