WARTY DYSKERATOMA

Abs1ract. A case is rcported of a 53-)car-old "oman. "ho had had ror one ycar a wart-like papillomatous lesion on the alveolar process in the region corresponding 10 -,-8. The remaining mucosa exhibited a normal clinical picture. The patient's general health was satisfactory and no skin mani­ festations ot interest "ere apparcnt. The lcsion was cxtirpatcd and cxamined histologically and microradiographically and was found to have histopathological characteristics of thc same kind as in warty dyskeratoma. The discussion is con­ cerned with actiological factors and with problems of difrcr­ ential diagnosis.

Warty dyskeratoma or dyskeratoma vcrruciformis is a benign tumour which usually occurs in the form of a solitary, well circumscribed and wart-like lesion on the scalp. face or neck, or even on the back, chcsl, abdomen or extremities, occasionally also in the oral cavity (24). The disease was first describcd by Allen (I) and Helwig ( 12) under the name ••iso latcd Daricr·s diseuse .. , since its histopa1hological picture Jargely resembled that found in Darier·s discase or dyskeratosis follicularis-a dominant hered itary skin disease which preferentially manifests it self in the form of wart-like papules on 1hose areas of skin whcre therc are sebaceous glands (10).
Warty dyskeratoma has been reportcd to occur in the oral mucosa too ( 11,24). In view of the pau city of cascs reported in the literature, and of the problems of differential diagnosis which may arise owing to the limited experience possessed of this type of tumour, it was considered worthwhile lo report a case of warty dyskeratoma in tbe oral cavity.

CASE REPORT
The patient. a 53-year-old woman, was referred to the Dc partment of Oral Surgcr) of thc Rcgionnl Hospital, Linköping, for a mucosal lesion in the region corresponding 10 + 8.
For one ycar the patient had bcen able to fec I" ith her tonguc a lesion situatcd on thc alveolar process distal to 8. The patien1·s general state of hcullh was normal and no skin manifostations of interest were found; nor "as there any hercditary background 10 thc lesion.
The patient had normal dcntilion in the upper jaw and her dental status was satisfactory. Clinical inspcction re vealcd a 5 5 mm leukoplakia-like lesion with a papillomatous. wart-like appearancc 011 the alveolar process distal to + 8. The remaining oral mucosa re,caled a normal clinical picture. No lymph glands "ere palpable. X-ra) failed 10 re,eal any abnormality.
Some of the sections "ere used for microradiography on the principles for con1ac1 microradiograph) presented by Engström & Lindström (7) and Lindström ( 17). The X-ray tube was dcsigned by Engström & Lundberg (8). The voltage wa� 3.0 kV and amperage 200 mA. The cmiued, cominuous X-ray spcctrunt was fillered throur;h a thin otuminium filter. With the voltagc and 1hickness of filter used, most or thc cmittcd X-ray quanta had wavelengths bet,.een 8 and 11 Å ( 19). The contrusts on the developed microradiogram were caused by variations in the dry weight distribution of thc various organic tissue componems.
For the histological production of the microradiograms the techniquc used was that dcscribed by Engs1röm et al. (9). The tissue scctions were placed al a distance or about 55 mm from focus, which was about 0.1 mm in diameter.

HISTOPATHOLOGICAL AND MICRORADIO GRAPHIC FINDLNGS
The sample consists of a well delimited soft tissue tumour which grows down from the epithclium into the connective tissue. The piece of tissue is covered with a hyperparakeratotic and hyperorthokeratotic stratified squamous epithelium exhibiting acantho- In some cases the nucleus may be cntirely dissolved and has thcn been replaced by keratin masses of high dry weight concentration (Fig. 4). The "grains .. resemble parakcratotic cells but are rather larger and in some cascs have an elongated, basophilically stained and often pyknotic nucleus which in most cases is surrounded by a narrow cytoplasmic zone (Fig. 3). These cells may have the form of dyskeratot ic cells in the horny layer, or of dyskeratotic and acantholytic cells within the Jacunae.
A moderate, chronic, non-specific inflammation is seen in the connective tissue (Fig. I). The boundary betwcen epithelium and connective tissue is sharp, the mitotic activity low, and thcre is no evidence of infiltrative growth or of malignity.

DISCUSSION
The advantage of using ultrasoft X-rays for studying the keratinization in epithelium of the human oral mucosa was demonstrated by Anneroth (2,3). Mor phological and chemical changes occur in the tissue <luring the histological treatment of the kind em ployed (6,21 ). Therefore, the morphological and chemical status of the tissue sections do not corre spond to that intra vitam, presumably because most of the lipids, carbohydrate, and electrolytes have been dissolved from the tissue specimens duriog the histotechnical procedure.
These factors also affect the evaluation of the dry mass distribution in the microradiographs. However, the latter still provide valuable information con cerning the morphological localization of the nucleic acids and proteins present in the tissue sections. Proteins constitute thc main part of the roentgen absorbing material. As keratin has a high dry mass and consequently appears as a dense area in the microradiographs, the contact microradiographic technique using ultrasoft X-rays is a very suitable method for morphological investigation of chaoges in the dry mass concentration at warty dyskeratoma, where a disturbaoce in the keratinization process has occu�red.
Darier's disease (dyskeratosis follicularis) is a dominant, autosomal disease manifesting itself as hyperkeratotic papules which, apart from in the skin, occur dispersed in the mucosa of the vulva, vagina, rectum, larynx, pharynx and in the oral cavity. The Warry dyskeratomu or dyskeratoma urruciformis is a rarely occurring, solitary lesion on the skin or in the oral mucosa and which rcsembles Darier·s diseasc clinically and histopathologically (23). Gor lin & Peterson ( 11) were the first 10 report a case of wany dyskeratoma-in the oral mucosa in a 45year-old man.
The aetiology of warty dyskeratoma is unknown. Szymanski (22) and Graham & Helwig (10) reported virus LO be the probable cause. S1ymanski (22) con sidered the virus to be closely allied lo that found in warts, while Graham & Helwig ( I 0) presumed it to have a special predilection for pilo-scbaceous structures and that it h::id the abilily to destroy hair and �ebaceous glands. Nor is the causc of warly dyskcraloma in the oral mucosa known. Heterotopic .. pilo-sebaceous struc tures .. may arise in the oral cavity in relation to Fordyce's spots (20), but Gorlin & Peterson t 11 ), like Tomich & Burks (24), considered it scarcely Acra Dermatouner (S1ocklw/111) 55 probable that warty dyskeratoma arises from pilo sebaccous structures in the oral mucosa. since such sebaceous glands arc cxtremcly rare in the oral mucosa (14). Tomich & Burks (24) serially sectioned their material and found no evidence of sebacous glands in connection with the lesion. They presumcd that '·perhap:, a viru� with an affinity for oral epithclial cells phylogenetically related to and re taining the pluripotentiality of cutaneous cpithelium is the ctiologic factor responsible for the histopalho gencsis of the mucosal warty dyskeratoma".
Tomich & Burks {24) reported three cases or \\arty dyskeratoma in the oral mucosa, all being men, aged 49-61 years, In two cases the lesions were located in a toothless alveolar process in the lower jaw. in the third case in the palatinal, marginal gin giva in the region of 7. The case described in the present paper is, as far as we know, the only one published in which the patient was a woman.
Even if the histopathological picture of warty dyskeratoma largely resembles that found in Darier's disease. the clinical pictur�as also the absence or autosomal, dominant heredity-of warty dysker atoma suggests that it is a matter of two separate disease entities. Warty dyskeratoma does not occur as a preliminary stage of Darier's disease.
Warty dyskeratoma and ramilial benign pemphi gus havc common histopathological characteristics in the form of parakeratosis, dyskeratosis and supra basal separation of the epithelium, caused by acan tholysis, and a proliferation of villi-like connective Lissue papillae into lacunae or vesicles.
From the differential diagnostic aspect, warty dyskeratoma differs from ramilial benign pemphigus in its usually less pronounced suprabasal separation and the fact that the acantholysis and dyskeratosis are less prominent and are limited chiefly to the basal region. Dyskeratotic cell changes, as also the occur rence of "corps ronds" and "grains". are more prominent in warty dyskeratoma than in familial benign pemphigus.
Jablonska & Chorzelski (13) considered that warty dyskeratoma was associated with senile (actinic) keratosis, since the disease often occurred in elderly patients and exhibited histopathological symptoms of the kind often found in warty dyskeratoma in the form of, inter alia, basal lacunae and dysker atosis. Metz & Schröpl (I 8) considered it probable that senile keratosis represented a transitional stage to warty dyskeratoma. Delacretaz (4,5), however, considered there to be no correlation between these two affections, since cases of warty dyskeratoma had been found in the lowcr part of the hair-follicle, while the overlying skin was of normal appearance.
Warty dyskeratoma, like naevus syringadenomato sis papilliferus or syringocystadenoma papilliferum, grows down from the surface and forms invagina tions. Lacunae containing villi also occur. A homy plug may be present, but corps ronds or grains do not exist in naevus syringadenomatosis papilliferus. In the latter disease the cavities and villi are lined with double rows of cells, whereas the villi-like con nective tissue papillae of warty dyskeratoma are covered witb a single layer of cells. The cells which line the cystic cavity in naevus syringadenomatosis papilliferus, furthermore, exhibit decapitation secre tion, which has not been observed in warty dyskera toma. Whereas in warty dyskeratoma there is a Warry dyskeratoma 231 mild chronic inflammation in a narrow zone round the tumour, in the sweat gland tumour there is a pronounced infiltration of plasma cells.
Jablonski & Chorzelski ( I 3) spoke of the possi bility of a transition from warty dyskeratoma to a dyskeratotic cancer lesion. Lever (15) classifies warty dyskeratoma as a precancerous tumour, but recog nizes at the same time that 110 case of warty dyskera toma in the skin has proceeded to a malignant stage.
All cases or warty dyskeratoma reported in the oral mucosa, furthermore, have exhibited a benign dys keratosis with no sign of malignity.