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Clear Cell Acanthoma: A Widely Unknown Tumor-like Dermal Lesion
Beitr. Path. Bd. 156, 173-178 (1975)
Rare and Unusual Cases
Pathologisches Institut der Universitat des Saarlandes, Homburg/Saar (Direktor: Prof. Dr. G. Dhom)
Clear Cell Acanthoma: A Widely Unknown Tumor-like Dermal Lesion Klarzell-Akanthom: eine weitgehend unbekannte Hautlasion H. B. VON SEEBACH, ANNEGRET VON SEEBACH!) and G. KLINGMDLLER2)
With 3 Figures' Received January 5, 1975 . Accepted February 12, 1975
Key words: Clear cell acanthoma - Skin tumors - Acanthoma - Degos acanthoma - Epidermal glycogen accumulation
In 1962 Degos et al. described a theretofore unknown dermal tumor which they designated as clear cell acanthoma ("acanthome cellules c1aires"). More than 100 cases have since been described (Degos and Civatte, 1970), but only scarcely in the pathological literature (Brownstein et aI., 1973). Especially for the diagnostic pathologist doing routine biopsy studies the characteristics of this widely unkown dermal tumor are described.
a
Clinically, clear cell acanthoma appears as a prominent almost always solitary, light red tumor, localized mainly at the lower limb. On the surface serous crusts or a serous exudate with petechiae are seen. There seems to be no sex predilection. About half of the patients are older than 60 years. The lesion usually does not change its appearance over months or even several years. A spontaneous involution has not been observed. The clinical picture is not characteristic and excision is usally performed 1) FA. f. Hautkrankheiten, D-666 Zweibriicken, Karlstr. 12. 2) Universitats-Hautklinik, D-53 Bonn-Venusberg.
I74 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller under one of the following diagnoses: basal cell epithelioma, dermatofibroma, telangiectatic granuloma, Bowen's disease, senile whart, squamous cell carcinoma or perhaps eccrine poroma.
Histologically, there is an impressive acanthotic thickening of the epidermal layer. The papillae are elongated and either plump or narrow and exhibit net-like branching (Fig. 2 and 3). Spongiosis is prominent and the desmosomes are clearly recognizable. The keratinocytes show a light cytoplasm containing abundant glycogen as shown by histochemical procedures or electron microscopy (Fig. I and 2). The formation of regular epidermal layers is inhibited, and especially the granular layer is lacking. On the surface only a narrow parakeratotic horny layer is seen which may be covered with fibrin und nuclear debris. Mitotic figures are usually not increased. The glycogen accumulation markedly excepts the epithelia of the hair shafts and the acrosyringium of the sweat-
fig.!. Periphery of a clear cell acanthoma with the characteristic sharp borderline of epidermal glycogenosis. A transitional acanthotic zone with dilated capillaries is also recognizable. PAS-hematoxylin; X 130.
Clear Cell Acanthoma . I75
gland ducts (Fig. 3) and shows a sharp borderline to the normal epithelium in the vicinity of the tumor (Fig. I). The papillary dermal stroma contains an increased number of often dilated and convoluted capillary vessels (Fig. 2). They contain erythrocytes and fibrin as well as a large number of leukocytes, of which a greater amount is also found in the stroma (Fig. 3). Within the acanthotic epidermis small "microabscesses" may be found, containing epithelial cellular debris and leukocytes. Variants with a less pronounced inflammatory component were described (Ked, 1973).
Discussion There is agreement in the literature about the benignity of the process. The arguments in favor of this statement are the long clinical history, the lack of a considerable proliferative activity and the sharp borderline to the normal vicinity.
Fig. 2. Elongated and thickened epidermal ridges with intensive epithelial glycogen accumulation. Note dilated capillaries reaching the markedly thinned horny layer. PAShematoxylin; X 130.
176 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller
The main diagnostic criterion of clear cell acanthoma is an epithelial glycogen accumulation in a well circumscribed epidermal area. This phenomenon, being much more pronounced than in cases of irritated seborrhoic keratosis and eccrine poroma, leads to the tumor-like thickening of the epidermis which is, therefore, mainly caused by an increase in cytoplasmic mass of the single epithelial cells. Using the criteria of General Pathology as a measure, the morphologic picture is not that of a true tumor. Perhaps this is the reason for the fact that the lesion, despite being so!typical, i~was recognized so late as an independent entity and is so widely unknown. When the histologist does not see the tumor-like clinical picture, he may easily be satisfied with a descriptive diagnosis. Thus, there are only few arguments in favor of the assumption that we are dealing with a hamartoma of the surface epidermis, as is usually discussed in the literature. The histologic picture seems to us much more of a reactive nature, perhaps on the basis of inflammatory processes, as Duperrat et al. (1966) argued. Reports about the development of multiple clear cell acanthomas - a rare event - on the basis of preexisting dermal lesions point in the same direction. In the cases published by Thorne and Fusaro (1971) and Landry and Winkelmann (1972) an ichthyosis was the underlying disease and also the case by Ebner (1974) showed an unclassified scaling dermatosis. The glycogenic acanthosis of the esophagus (Clt~men~on and Gloor, 1974) perhaps represents a comparable reaction of an irritated epithelial surface. The lesion is probably not so rare as the scarce pathological literature suggests. Perhaps the designation as "clear cell acanthosis" would meet its character better.
References Brownstein, M. H., Fernando, S., and Shapiro, L.: Clear cell acanthoma: Clinico-pathologic analysis of 37 new cases. Amer. J. Clin. Path. 59, 306-311 (1973) Clemenc;on, G., and Gloor, F.: Benign epithelial hyperplasia of the esophagus: Glycogenic acanthosis. Endoscopy 6, 214-217 (1974) Degos, R., Delort, J., Civatte, J., et Baptista Poiares, A.: Tumeur epidermique d'aspect particulier: Acanthome a cellules claires. Ann. Derm. Syphiligr. 89, 361-371 (1962) Degos, R., and Civatte, J.: Clear cell acanthoma: Experience of 8 years. Brit. J. Dermatol. 83,24 8- 2 54 (197 0 )
Fig. 3. Scattered leukocytic infiltration of the cutaneous stroma in the vicinity of capillaries and involving the epidermis. The acrosyringium does not take part in the glycogen accumulation, thus being clearly recognizable. HE; X 160.
Clear Cell Acanthoma . 177
Fig. 3
17 8 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller Duperrat, B., Mascaro, J.-M., et Mascaro-Galy, c.: Sept cas d'acanthome a cellules claires. Arch. Belg. Derm. Syphiligr. 22,55-59 (1966) Ebner, H.: Multiple Klarzellakanthome. Z. Hautkrankh. 49, 541-546 (1974) Kerl, H.: Ober das Klarzellakanthom (Degos). Z. Haut- u. Geschlechtskrankh. 48, 20521 3 (1973) Landry, M., and Winkelmann, R. K.: Multiple clear cell acanthoma and ichthyosis. Arch. Dermatol. 105, 371-383 (1972) Thorne, E. G., and Fusaro, R. M.: Multiple clear cell acanthomas III a patient with lamellar ichthyosis. Dermatologica 143, 105-IIO (1971) Dr. H. B. von Seebach, Pathologisches Institut, Universitat des Saarlandes, D-665 Homburg (Saar)
Rare and Unusual Cases
Pathologisches Institut der Universitat des Saarlandes, Homburg/Saar (Direktor: Prof. Dr. G. Dhom)
Clear Cell Acanthoma: A Widely Unknown Tumor-like Dermal Lesion Klarzell-Akanthom: eine weitgehend unbekannte Hautlasion H. B. VON SEEBACH, ANNEGRET VON SEEBACH!) and G. KLINGMDLLER2)
With 3 Figures' Received January 5, 1975 . Accepted February 12, 1975
Key words: Clear cell acanthoma - Skin tumors - Acanthoma - Degos acanthoma - Epidermal glycogen accumulation
In 1962 Degos et al. described a theretofore unknown dermal tumor which they designated as clear cell acanthoma ("acanthome cellules c1aires"). More than 100 cases have since been described (Degos and Civatte, 1970), but only scarcely in the pathological literature (Brownstein et aI., 1973). Especially for the diagnostic pathologist doing routine biopsy studies the characteristics of this widely unkown dermal tumor are described.
a
Clinically, clear cell acanthoma appears as a prominent almost always solitary, light red tumor, localized mainly at the lower limb. On the surface serous crusts or a serous exudate with petechiae are seen. There seems to be no sex predilection. About half of the patients are older than 60 years. The lesion usually does not change its appearance over months or even several years. A spontaneous involution has not been observed. The clinical picture is not characteristic and excision is usally performed 1) FA. f. Hautkrankheiten, D-666 Zweibriicken, Karlstr. 12. 2) Universitats-Hautklinik, D-53 Bonn-Venusberg.
I74 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller under one of the following diagnoses: basal cell epithelioma, dermatofibroma, telangiectatic granuloma, Bowen's disease, senile whart, squamous cell carcinoma or perhaps eccrine poroma.
Histologically, there is an impressive acanthotic thickening of the epidermal layer. The papillae are elongated and either plump or narrow and exhibit net-like branching (Fig. 2 and 3). Spongiosis is prominent and the desmosomes are clearly recognizable. The keratinocytes show a light cytoplasm containing abundant glycogen as shown by histochemical procedures or electron microscopy (Fig. I and 2). The formation of regular epidermal layers is inhibited, and especially the granular layer is lacking. On the surface only a narrow parakeratotic horny layer is seen which may be covered with fibrin und nuclear debris. Mitotic figures are usually not increased. The glycogen accumulation markedly excepts the epithelia of the hair shafts and the acrosyringium of the sweat-
fig.!. Periphery of a clear cell acanthoma with the characteristic sharp borderline of epidermal glycogenosis. A transitional acanthotic zone with dilated capillaries is also recognizable. PAS-hematoxylin; X 130.
Clear Cell Acanthoma . I75
gland ducts (Fig. 3) and shows a sharp borderline to the normal epithelium in the vicinity of the tumor (Fig. I). The papillary dermal stroma contains an increased number of often dilated and convoluted capillary vessels (Fig. 2). They contain erythrocytes and fibrin as well as a large number of leukocytes, of which a greater amount is also found in the stroma (Fig. 3). Within the acanthotic epidermis small "microabscesses" may be found, containing epithelial cellular debris and leukocytes. Variants with a less pronounced inflammatory component were described (Ked, 1973).
Discussion There is agreement in the literature about the benignity of the process. The arguments in favor of this statement are the long clinical history, the lack of a considerable proliferative activity and the sharp borderline to the normal vicinity.
Fig. 2. Elongated and thickened epidermal ridges with intensive epithelial glycogen accumulation. Note dilated capillaries reaching the markedly thinned horny layer. PAShematoxylin; X 130.
176 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller
The main diagnostic criterion of clear cell acanthoma is an epithelial glycogen accumulation in a well circumscribed epidermal area. This phenomenon, being much more pronounced than in cases of irritated seborrhoic keratosis and eccrine poroma, leads to the tumor-like thickening of the epidermis which is, therefore, mainly caused by an increase in cytoplasmic mass of the single epithelial cells. Using the criteria of General Pathology as a measure, the morphologic picture is not that of a true tumor. Perhaps this is the reason for the fact that the lesion, despite being so!typical, i~was recognized so late as an independent entity and is so widely unknown. When the histologist does not see the tumor-like clinical picture, he may easily be satisfied with a descriptive diagnosis. Thus, there are only few arguments in favor of the assumption that we are dealing with a hamartoma of the surface epidermis, as is usually discussed in the literature. The histologic picture seems to us much more of a reactive nature, perhaps on the basis of inflammatory processes, as Duperrat et al. (1966) argued. Reports about the development of multiple clear cell acanthomas - a rare event - on the basis of preexisting dermal lesions point in the same direction. In the cases published by Thorne and Fusaro (1971) and Landry and Winkelmann (1972) an ichthyosis was the underlying disease and also the case by Ebner (1974) showed an unclassified scaling dermatosis. The glycogenic acanthosis of the esophagus (Clt~men~on and Gloor, 1974) perhaps represents a comparable reaction of an irritated epithelial surface. The lesion is probably not so rare as the scarce pathological literature suggests. Perhaps the designation as "clear cell acanthosis" would meet its character better.
References Brownstein, M. H., Fernando, S., and Shapiro, L.: Clear cell acanthoma: Clinico-pathologic analysis of 37 new cases. Amer. J. Clin. Path. 59, 306-311 (1973) Clemenc;on, G., and Gloor, F.: Benign epithelial hyperplasia of the esophagus: Glycogenic acanthosis. Endoscopy 6, 214-217 (1974) Degos, R., Delort, J., Civatte, J., et Baptista Poiares, A.: Tumeur epidermique d'aspect particulier: Acanthome a cellules claires. Ann. Derm. Syphiligr. 89, 361-371 (1962) Degos, R., and Civatte, J.: Clear cell acanthoma: Experience of 8 years. Brit. J. Dermatol. 83,24 8- 2 54 (197 0 )
Fig. 3. Scattered leukocytic infiltration of the cutaneous stroma in the vicinity of capillaries and involving the epidermis. The acrosyringium does not take part in the glycogen accumulation, thus being clearly recognizable. HE; X 160.
Clear Cell Acanthoma . 177
Fig. 3
17 8 . H. B. von Seebach, Annegret von Seebach and G. Klingmiiller Duperrat, B., Mascaro, J.-M., et Mascaro-Galy, c.: Sept cas d'acanthome a cellules claires. Arch. Belg. Derm. Syphiligr. 22,55-59 (1966) Ebner, H.: Multiple Klarzellakanthome. Z. Hautkrankh. 49, 541-546 (1974) Kerl, H.: Ober das Klarzellakanthom (Degos). Z. Haut- u. Geschlechtskrankh. 48, 20521 3 (1973) Landry, M., and Winkelmann, R. K.: Multiple clear cell acanthoma and ichthyosis. Arch. Dermatol. 105, 371-383 (1972) Thorne, E. G., and Fusaro, R. M.: Multiple clear cell acanthomas III a patient with lamellar ichthyosis. Dermatologica 143, 105-IIO (1971) Dr. H. B. von Seebach, Pathologisches Institut, Universitat des Saarlandes, D-665 Homburg (Saar)