Dermoscopy of non-pigmented eccrine poromas: study of Mexican cases

Background: Eccrine poroma is a benign neoplasm that can mimick a malignant neoplasm dermoscopically. The characteristic vascular pattern of this tumor has not been established. Objective: To evaluate dermoscopic features of non-pigmented eccrine poroma in Mexican patients. Method: We retrospectively studied histologically proven cases of eccrine poroma from three Mexican hospitals analyzed by four dermoscopists. Results: Thirteen cases were studied. A polymorphous vascular pattern was found in most cases. Four presented with irregular linear and branched vessels with semi-elliptical, or semicircular endings (“chalice-form” and “cherry-blossoms” vessels). Structureless pink-white areas were the most common other dermoscopic finding. Conclusions: “Chalice-form” and “cherry-blossom” vessels have not been reported in other benign or malignant neoplasms and can be a useful clue to the diagnosis of non-pigmented eccrine poroma. Due to the variability of dermoscopic patterns of eccrine poroma further studies are required to establish the specificity of our findings.


Material and methods
This is a retrospective study, including histologically veri- When multiple lesions appear on palms and soles the condition has been termed eccrine poromatosis [1,2].
Dermatopathologically it is a proliferation arising from the lower portion of the epidermis from where it extends into the dermis forming a mass or broad anastomosing bands, composed of epithelial cells with uniform cuboidal appearance with round basophilic nuclei, connected by intercellular bridges. In the majority of cases, small ducts and occasionally cystic spaces are found within the aggregations of tumor cells [3].
Dermoscopy is a non-invasive technique that is useful for the diagnosis of benign and malignant melanocytic and non-melanocytic lesions. In general the presence of a polymorphous vascular pattern is considered to be a useful clue to differentiate between benign and malignant neoplasms.
Vascular patterns, including morphology and distribution of vessels, can be useful to make a specific diagnosis, especially in combination with other structures. However, only a few articles describe the dermoscopic features of non-pigmented EP [4][5][6][7]. Since the number of published articles is small, spe- *"frog-egg appearance" (38%) Research | Dermatol Pract Concept 2012;3(1):7

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The dermoscopic features are presented in Table 1. We found no differences with regard to dermoscopic structures seen with polarized light with immersion and polarized light without immersion. Nine cases (70%) showed a polymorphous vascular pattern, including at least two types of vascular structures; four of them (30%) showed irregular linear vessels with a semi-elliptical ending giving the appearance of a chalice ("chalice-form"). In addition to "the chalice-form" vessels, three cases (23%) also showed structures combining thin branching vessels with circular and semicircular tips, very similar to the structure of the cherry blossom tree; and, in addition, one of these displayed a small ulceration (Figures 1, 2, 3). One more case showed "cherry-blossom" vessels in the center of the lesion and milky-red globule/ lacuna-like areas surrounded by pink-to-white halo ("frogegg" aggregations) in the periphery. Four more cases (in total

Results
We included 13 cases of 6 women and 7 men.    characteristic of non-pigmented EP in of our series, were also found in most cases in the study of Ferrari et al [6]. The well-circumscribed milky-red lacunas separated by whitepink bands, the "frog-egg" appearance, which were seen in five (38%) of our patients, were also found in 90% of cases studied by Minagawa et al [9].

Conclusion
The "chalice-form" and "cherry-blossom" vessels are a good clue for the diagnosis of non-pigmented EP, although, for unknown reasons, the pattern of non-pigmented EP is not uniform, and further studies are required to establish the specificity of our findings. 38%) show these "frog-egg" aggregations ( Figure 4) and the rest of the cases combined linear irregular, hairpin vessels in addition to milky-red globules-like areas. In nine cases (70%) a structureless pink-to-white area was found, the most frequently found non-vascular structure.  [4,[6][7][8][9]. This pattern is characterized by the presence of irregular vessels that vary in size and shape and by the combination of different types of vessels. The vascular pattern of cases reported by Aydingoz [8] was described as "floral and leaf-like." We propose to call these vessels "chalice-form" and "cherry-blossom vessels" because of their similarity with a chalice and because the branches resemble the flowers of cherry trees. We consider these terms easy to remember. These vascular patterns seem to combine hairpin and branched vessels and have not been reported as part of the vascular pattern of melanoma or other malignant tumors [5,10]. Therefore, the presence of this vascular pattern could be a helpful clue in differentiating EP from other benign or malignant non-pigmented neoplasms. However, given the small number of cases in our study, it would be premature to consider these vessels specific for eccrine poroma.
Although in other studies glomerular, arborizing and linear irregular vessels were dominant, we barely found them in our series. Structureless pink-to-white areas, a dominant