Clear cell syringoma

ARTICLE

A 40-year-old Philippino woman presented with multiple small papules on both lower eyelids and the upper part of her cheeks. None of her family members had similar lesions. Although she had been treated with insulin for diabetes mellitus since 1994, the control of the disease was poor. The papules appeared in 1997 and have gradually increased in number. Physical examination revealed many flesh-colored or slightly reddish, smooth-surfaced, half-grain sized papules on her lower eyelids and the upper part of her cheeks (Fig. 1). Abnormal laboratory data were as follows: triglyceride: 255 mg/dl (35-130 mg/dl); blood sugar: 285 mg/dl (2 hrs after meal); hemoglobin A1c: 10.2% (4-6%). Histopathological examination revealed some cell nests consisting of clear cells in the upper dermis. The cell nests were surrounded by fibrous stroma, and contained amorphous material in the intraductal space. The clear cell had a large vacuolated cytoplasm with a small hyperchromatic nucleus in the pericytoplasm (Fig. 2). Periodic acid-Schiff (PAS) staining showed reactive spots in the cytoplasm and the intraductal space. The PAS-positive reaction was diminished after diastase digestion.

Clear cell syringoma

Both clinical and pathological findings are considered to be consistent with clear cell syringoma. Although the re-initiated therapy for diabetes mellitus has controlled her disease well, the papules have remained unchanged.

Comments

Clear cell syringoma was first described by Headington et al. in 1972 [1]. It has been recognized to be one of the dermadromes associated with diabetes mellitus [2]. In most cases, multiple miliary-sized papules are seen on both eyelids. In some cases [3], however, the papules become larger than ordinary syringoma as in our case. Although clear cells are sometimes noted in ordinary syringomas, the cells in clear cell syringoma are inclined to proliferate and have a smaller nucleus and dense chromatin [4].

The pathogenesis of clear cell syringoma is still unknown. The PAS-positive substance in the clear cell is considered to be glycogen [5]. Phosphorylase activity in clear cell syringoma was reported to be suppressed in some cases [1, 6]. Headington inferred that the clear cells undergo glycogenesis because of a relative deficiency in phosphorylase [1]. In contrast, Saitoh et al. [7] claimed that phosphorylase activity in syringoma may be normal, but elevated glucose levels in diabetics may suppress the activity. Recently, Ohnishi et al. demonstrated that clear cell syringoma showed differentiation into the transitional portion between the acrosyringium and the dermal duct, as in conventional syringoma [8]. They concluded that clear cell syringoma is a metabolic variant of ordinary syringoma.

References

1. Headington JT, Koski J, Murphy PJ. Clear cell glycogenosis in multiple syringoma. Arch Dermatol 1972; 106: 353-6.

2. Nakabayashi Y, Niimura M, Hori Y. A case of clear cell syringoma (in Japanese). Rinsho Dermatol (Tokyo) 1980; 22: 599-603.

3. Takeshige M, Yamamoto A, Inomata N. Clear cell syringoma with milia-like papules (in Japanese). Jpn J Clin Dermatol (Tokyo) 1988; 42: 19-23.

4. Nakamura Y, Sueki H, Yasuki Y, Iijima M, Fujisawa R. A case of clear cell syringoma (in Japanese). Jpn J Clin Dermatol (Tokyo) 1991; 45: 891-5.

5. Feibelman CE, Maize JC. Clear-cell syringoma. A study by conventional and electron microscopy. Am J Dermatopathol 1984; 6: 139-50.

6. Furue M, Hori Y, Nakabayashi Y. Clear-cell syringoma, association with diabetes mellitus. Am J Dermatopathol 1984; 6: 131-8.

7. Saitoh A, Ohtake N, Fukuda S, Tamaki K. Clear cells of eccrine glands in a patient with clear cell syringoma associated with diabetes mellitus. Am J Dermatopathol 1993; 15: 166-8.

8. Ohnishi T, Watanabe S. Immunohistochemical analysis of keratin expression in clear cell syringoma. J Cutan Pathol 1997; 24: 370-6.