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P Simón

Publications and source records attributed to P Simón.

16 recordsLinked to original sources
PubMed1998

Stimulation of folliculo-sebaceous proliferations by neurofibromas: a report of two cases.

Two unrelated patients, a woman aged 44 and a man aged 56, with a type I neurofibromatosis, showed comedo-like formations at the top of some neurofibromas. One of them was excised in each case and they were studied histopathologically. The comedo-like formation of the first case mimicked the epithelial component of a fibrofolliculoma, and that of the second case had the structure of a primary late microcomedo and showed also anagen hair differentiation in the form of a follicular bulb and papilla. Both events are considered to be the result of a stimulation phenomenon and to reflect the essential role of the stroma in many cutaneous epithelial hyperplasias, hamartomas and possibly in some neoplasms.

Adult↗
PubMed1997

The histopathology of closed and open comedones of Favre-Racouchot disease.

OBJECTIVE: To determine the distinction between a comedo and an infundibular cyst of Favre-Racouchot disease. SETTING: A university hospital. PATIENTS: From the 8 patients included in the study, 19 cysts and comedones were evaluated. MAIN OUTCOME MEASURE: The distinguishing features between the cysts and comedones of Favre-Racouchot disease. RESULTS: All lesions were histologically indistinguishable from the primary comedones of acne vulgaris, except for the presence of a marked actinic elastosis in the surrounding dermis. The presence of a variable number of hair shafts and an abundant amount of bacteria, which was positive in the results of Gram staining and periodic acid-Schiff reaction and intermingled with sebum and eosinophilic laminated horny material within the dilated infundibulum, characterizes a comedo and differentiates it from an infundibular cyst. CONCLUSIONS: The cysts and comedones of Favre-Racouchot disease are closed and open comedones. They can be easily differentiated from an infundibular cyst by the histopathologic features rather than by the connection to the surface.

Aged↗
PubMed1995

Sebomatricoma: a unifying term that encompasses all benign neoplasms with sebaceous differentiation.

Literature regarding neoplasms with sebaceous differentiation is confusing, particularly concerning the concept of sebaceous epithelioma, accepted by some observers as a specific neoplasm but defined by others as basal cell carcinoma with sebaceous differentiation and still others as sebaceous adenoma in which undifferentiated basaloid cells predominate. From our study of 19 benign sebaceous neoplasms within this spectrum and a critical review of the literature, we conclude that (a) "sebaceous epithelioma" is a nonuseful term; (b) the term "basal cell carcinoma with sebaceous differentiation" should be used only for an otherwise conventional basal cell carcinoma with histological evidence of sebaceous differentiation; (c) "sebaceous adenoma," as described by Troy and Ackerman, represent polar ends of the spectrum of a benign neoplasm with varying degrees of sebaceous differentiation, for which we propose the term "sebomatricoma"; and (d) sebomatricoma, so defined, embraces such diverse benign neoplasms with sebaceous differentiation as superficial epithelioma with sebaceous differentiation and previously "unclassifiable" sebaceous neoplasms, often found in patients with Muir-Torre syndrome or within nevus sebaceus of Jadassohn.

Adenoma↗
PubMed1993

Histopathology of cutaneous changes in drug-induced coma.

Present knowledge of the histopathology of cutaneous changes seen in drug-induced coma is very incomplete: Only 1 of the 11 papers on this subject mentions follicular or sebaceous gland damage, with very little attention focused on vascular changes. We made a careful study of serial sections from eight cutaneous biopsy specimens from seven patients who suffered drug-induced coma with the following findings: (a) The secretory portion of the eccrine sweat coil is the epithelium most susceptible to necrosis. It is followed by, ex aequo, eccrine sweat duct, hair follicle, and sebaceous gland, and, lastly, the epidermis. (b) In the eccrine sweat duct, the outer root sheath of the hair follicle, and the epidermis, necrosis does not usually appear first in the outermost (basal cell) layer. (c) Necrosis of the outer root sheath of the telogen "club" follicle is usually more advanced than that of the secondary hair germ, and, at times, a spared anagen bulb can be seen in closest proximity. (d) Vascular changes correlate proportionately with epidermal damage and consist of a largely neutrophilic inflammatory infiltrate and blood vessel wall damage, mainly involving arterioles. Our findings contradict the widely accepted hypothesis that pressure is the main cause of the cutaneous changes in drug-induced coma.

Adult↗
PubMed1993

Incidental acantholysis.

The incidental finding of microscopic foci of acantholytic dyskeratosis, reproducing the histological pattern of Darier's disease, has been the subject of a number of papers in the last few years. In contrast, the incidental finding of other types of acantholysis has not been mentioned in the literature. In the last 5 years, we have noticed such a microscopic finding in 14 biopsy specimens (0.15% of our cutaneous specimens). they were from 13 patients (7 men and 6 women); their ages ranged from 37 to 79 years (mean, 63). Three lesions were located on the head, 7 on the trunk, and 4 on the limbs. The histological diagnoses were basal cell carcinoma (6 cases), keratoacanthoma (2 cases), psoriasis (2 cases), elastolytic granuloma, acral arteriovenous angioma, tinea corporis, and leukocytoclastic vasculitis (1 case each). The histological patterns of the acantholytic foci simulated pemphigus vulgaris (9 cases), superficial pemphigus (1 case), Hailey-Hailey disease (3 cases), and unclassifiable acantholysis (1 case). None of the patients had familial or personal history of acantholytic disorders. We propose a classification of the primary acantholytic disorders based on both their acantholytic pattern and their clinical extent.

Acantholysis↗
PubMed1992

Complex adnexal tumor of the primary epithelial germ with distinct patterns of superficial epithelioma with sebaceous differentiation, immature trichoepithelioma, and apocrine adenocarcinoma.

A 60-year-old man came for treatment of a sharply outlined erythematous plaque on the gluteal area (45 x 20 mm) of 20 years' duration. Eccentrically located on the plaque was a nodule, 20 mm in diameter. Histological study of the plaque showed a superficial platelike tumor with basaloid bland cytology and sebaceous gland differentiation. Histologic study of the nodule found an undifferentiated adenocarcinoma whose ductlike glandular structures opened to the skin surface and infiltrated the whole depth of the dermis. Study of other areas of the lesion detected two more neoplasms. A nodule of squamous cell carcinoma was found within the superficial band of the benign sebaceous tumor. The fourth neoplastic pattern consisted of epithelial islands composed of basaloid cells within a fibroblastic stroma. There was prominent palisading of epithelial cell nuclei at the periphery of the islands, which usually were surrounded by a sheath of mesenchymal cells. In this complex adnexal tumor of the primary epithelial germ, sebaceous and follicular differentiation both simulate neoplastic patterns recently described as separate entities: superficial epithelioma with sebaceous differentiation and immature trichoepithelioma. The undifferentiated adenocarcinoma may represent differentiation toward the third component of the germ, that is, the apocrine gland.

Adenocarcinoma↗
PubMed1992

Basal cell carcinoma with matrical differentiation.

Three cases of basal cell carcinoma showing shadow cells within basaloid islands have been described using the term basal cell carcinoma with matrical differentiation for this histologic variant. We present four new cases of basal cell carcinoma with evidence of matrical differentiation. Unlike the cases previously published, these lesions showed nests of shadow cells either within the lobules of basaloid cells or forming nests in the stroma. We also noted the presence of a foreign body reaction and calcification. These neoplasms illustrate the capability of basal cell carcinoma to differentiate toward hair matrix cells. Basal cell carcinoma with matrical differentiation must be added to the uncommon variants of basal cell carcinoma showing adnexal differentiation. A parallel between the degrees of differentiation of the cutaneous sebaceous neoplasms with those showing matrical differentiation is proposed.

Aged↗
PubMed1986

Influence of the conjoint administration of insulin and glucagon upon hepatic regeneration.

In noneviscerated rats, the influence of the conjoint administration of insulin and glucagon in the regenerative response triggered by 70 per cent hepatectomy using the incorporation of tritiated thymidine by nuclear deoxyribonucleic acid as a parameter has been demonstrated. The response was earlier and more intense in relation to animals not hormonally stimulated and stimulated only with glucagon (previously reported by us). Such a response has been comparatively greater both in the nonparenchymal cells and in the hepatocytes, especially in the latter, which are the main cause of the early peak of thymidine incorporation in the periportal zones indicating a greater regenerative activity than in the intermediate and centrolobular zones. In our opinion, this indicates the importance of certain extrahepatic humoral agents in the manifestation of the regenerative process. Therefore, the results of our study ascertain the determining role and synergistic action of the pancreatic hormones--insulin and glucagon--in hepatic regeneration.

Animals↗