Biomedical subjects
Publications and source records attributed to P Robins.
Basal-cell carcinomas on covered, anatomically shielded, or otherwise unusual sites of the body are rare compared to the number on constantly exposed parts of the body, but since basal-cell carcinomas are so common, instances of the former sort are not infrequently encountered. Five such cases are described and illustrated.
Despite the high cure rate achieved for basal-cell carcinomas treated with microscopically controlled excision, recurrences do occur. To determine if lesions that are likely to recur may be predicted at the time of surgery, data from 5020 patients with 7010 basal-cell carcinomas treated with Mohs' technique were reviewed. Two thousand nine hundred sixty (2960) lesions with five-year follow-up were studied (overall recurrence rate = 2.6%). Sex and age of the patients, size and location of lesions, types of previous therapy, and the number of surgical stages of microscopically controlled excision were all found to correlate significantly with recurrence rate (p less than 0.01). Multiple regression analysis was performed to determine the relative contribution of each of these variables to predictability of recurrences by a weighted scoring system. The derived model delineated the lesions into no-risk, low-, medium-, and high-risk groupings (p less than 0.000001). Lesions in the high-risk group had a recurrence rate of 10.1%, almost four times greater than the average. More aggressive microscopically controlled excisions and closer follow-up care are indicated for those lesions that can be predicted to result in a high-risk score.
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Three cases of basal-cell carcinoma on and around the female genitalia are described. Two of these cases had multiple skin tumors on sun-exposed as well as on covered areas of the body. It is postulated that the biologic age of basal cells may be a factor in the genesis of skin cancer.
A search has been made for mutants of E. coli that are constitutive for the adaptive response to alkylating agents. When selection was for resistance to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) the resulting strains all proved to be low in intracellular thiols. As MNNG has to be converted by thiols to the proximal mutagen methylnitrosamine, these strains were resistant simply because their low thiol levels made them less readily methylated by MNNG. The selection was therefore undertaken for strains resistant to N-methylnitrosourea (MNU) because this alkylating agent does not require activation by thiols. Four MNU resistant mutants proved to be constitutive for the adaptive response. Following exposure to (3H) MNNG, they showed the same low ratio of O6-methylguanine (O6MeG) to 7-methylguanine (7MeG) as adapted wild type bacteria. The ratio of 3-methyladenine (3MeA) to 7MeG was the same in the wild type, the adapted wild type, and the constitutive strains. When exposed to very high MNNG doses, the constitutive mutants were even more resistant to mutation and killing than the adapted wild type. They have an even greater ability than the adapted wild type to remove O6MeG from methylated DNA (Lindahl personal communication).
Extensive analysis of ten factors in 183 consecutive cases of basal cell carcinoma overlying cartilage of the nose and ear is performed in this prospective study. Duration of tumor and prior treatment rather than one specific modality of previous therapy are significant factors in predicting tumor invasion of cartilage, which necessitates removal of cartilage.
The foregoing statements may invite controversy. At the same time, I hope they will be stimulating enough to lead many physicians to explore the various modalities open to them. Each case of skin cancer is an individual therapeutic problem, and the final decision as to what method should be used can be made only after every factor listed in Table 1 has been carefully weighed.
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With the introduction of the Mohs fresh-tissue technique, immediate repair of surgical wounds has become feasible in selected cases. In this article several case reports are presented to illustrate the use of primary closures, skin grafts, and flaps in an office facility.
Different local anesthetics have different physicochemical properties that result in different biological effects. Etidocaine (Duranest) is said to be a long-acting anesthetic with a rapid onset of action, properties that are particularly useful in busy office practices in which lengthy operative procedures are performed. Clinical testing confirmed that this anesthetic does, indeed, work in this manner, which makes it a good addition to the varieties of local anesthetics available.
Five cases of Bowen disease of the nail apparatus were studied and the 20 cases published to date reviewed. The lesion was characterized by either periungual redness with scaling and erosions, whitish cuticle, hyperkeratotic or papilomatous process, fissure or crusted ulcer in the lateral nail fold or the nail bed with eventual partial or total destruction of the nail plate and sometimes soreness on the pressure. The key of the diagnosis is the histological picture, identical with that of Bowen diseases of other skin areas. Among the 25 cases, Bowen disease was found mainly in males (20 out of 25 patients) on the left fingers (17 out of 25 finger lesions) with particular involvement of the 1st, 2nd, 3rd finger nail. Hallux was concerned twice. The clinical picture can be protean and mimic verrucae, onychomycosis, paronychia, eczema, pyogenic granuloma, verrucous tuberculosis, subungual exostosis, glomus tumor, dermatitis vegetans, amelanotic malignant melanoma, kerato-acanthoma and of course squamous cell carcinoma. Treatment of choice is complete removal of the tumor by plastic surgery otherwise microscopically controlled excision following chemical fixation (Mohs) or fresh tissue technique.
Cytoplasmic antigens of 3 different specificities are expressed concurrently in the epidermis of normal human skin. They differ by their location in distinct layers of the epidermis. One type is present in all epidermal cells, another only in cells of the superficial layers, and the third only in basal cells. All 3 antigens were present in 10 specimens of normal human skin. The superficial and basal cell antigens were absent in 4 basal cell epitheliomas and 3 squamous cell carcinomas. This finding, together with the stratification of the antigens in different layers of the skin, suggests epidermal cytoplasmic antigens are differentiation antigens.
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In a review of 848 successive cases of basal-cell carcinomas treated during 1976 in the Chemosurgery Unit of the New York University Medical Center by far most were found on the face and scalp (751/848 = 88.6%), and those in the triangle of the face formed by lines drawn from the outer canthi to the philtrum of the upper lip that includes the nose and its alae accounted for more than one-third of the entire number (316/848 = 37.2%) or two-fifths (316/764 = 41.4%) of those on the head and neck. Further analysis of our data showed the basal-cell carcinomas in the center of the face tended to be more invasive, more destructive, more recurrent, and more difficult to treat than were those in other sites. The reasons for seriousness and difficulty in management of basal-cell carcinomas and special diagnostic, prognostic, and therapeutic considerations pertaining to them are illustrated by representative case reports.
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Experience in treating 1, 275 skin cancers with Mohs' chemosurgery is presented. The Mohs technic uses microscopic examination to avoid excision of normal tissue and assure complete removal of the tumor. Chemosurgery is indicated for tumors which are poorly demarcated or which arise in areas known to have a high recurrence rate. It is the procedure of choice for almost all recurrent lesions.
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