Mutations in the human homologue of the Drosophila patched gene in Caucasian and African-American nevoid basal cell carcinoma syndrome patients

The nevoid basal cell carcinoma syndrome (NBCCS), or Gorlin syndrome, is a multisystem autosomal dominant disorder. The salient features of this syndrome include multiple basal cell carcinomas, palmar and/or plantar pits, odontogenic keratocysts, skeletal and developmental anomalies, and ectopic calcification. Other features include such tumors as ovarian fibromas and medulloblastomas. There is extensive interfamilial as well as intrafamilial variability with respect to the manifestation and severity of the phenotype. Alterations in the human homologue (PTCH) of the Drosophila segment polarity gene patched have been identified in NBCCS patients as well as tumors associated with this syndrome. We report several mutations in this gene in NBCCS patients and present the clinical phenotypes of the individuals in whom these mutations were identified.

Mutations of the human homolog of Drosophila patched in the nevoid basal cell carcinoma syndrome

The nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by multiple basal cell carcinomas (BCCs), pits of the palms and soles, jaw keratocysts, a variety of other tumors, and developmental abnormalities. NBCCS maps to chromosome 9q22.3. Familial and sporadic BCCs display loss of heterozygosity in this region, consistent with the gene being a tumor suppressor. A human sequence (PTC) with strong homology to the Drosophila segment polarity gene, patched, was isolated from a YAC and cosmid contig of the NBCCS region. Mutation analysis revealed alterations of PTC in NBCCS patients and in related tumors. We propose that a reduction in expression of the patched gene can lead to the developmental abnormalities observed in the syndrome and that complete loss of patched function contributes to transformation of certain cell types.

Use of relatives of cases as controls to identify risk factors when an interaction between environmental and genetic factors exists

BACKGROUND

The difficulty in detecting relevant risk factors for chronic diseases (such as breast and colon cancer) may be due to heterogeneity in the populations of studied cases, and one source of heterogeneity may be differential genetic susceptibility predisposing to differential environmental sensitivity.

METHODS

The purpose of this investigation is to determine whether the estimates of odds ratios are modified by using relatives as controls when risk factors interact with an underlying genetic factor.

RESULTS

We demonstrate that using relative controls in matched case-control studies produces odds ratios different from population-based odds ratios. This difference is dependent on the amount of interaction between the genetic and environmental factors and on the genetic correlation between relatives.

CONCLUSIONS

In the case of a common disease, the use of relatives as controls could be helpful in detecting interaction between an exposure and an underlying genetic factor when the genetic factor is common.

DR2/DQw1 inheritance and haplotype sharing in affected siblings from multiple sclerosis families

Although the human leukocyte antigen DR2/DQw1 allele has been associated with multiple sclerosis, studies of DR2/DQw1 inheritance in multiple sclerosis multiplex families have yielded conflicting results. We examined this question in "high-incidence" families, defined as families with more than 50% of siblings affected. DR2/DQw1 allele frequencies were significantly increased, particularly in mothers and affected siblings (p < 0.0001). The transmission of DR2/DQw1 from both parents was more frequent in affected offspring (p = 0.005). While evidence for segregation of disease with a particular parental allele was lacking in most families, the frequency of haplotype sharing was higher in affected sib pairs (p < 0.01).

Localization of the gene for Cowden disease to chromosome 10q22-23

Cowden disease (CD) (MIM 158350), or multiple hamartoma syndrome, is a rare autosomal dominant familial cancer syndrome with a high risk of breast cancer. Its clinical features include a wide array of abnormalities but the main characteristics are hamartomas of the skin, breast, thyroid, oral mucosa and intestinal epithelium. The pathognomonic hamartomatous features of CD include multiple smooth facial papules, acral keratosis and multiple oral papillomas. The pathological hallmark of the facial papules are multiple trichilemmomas. Expression of the disease is variable and penetrance of the dermatological lesions is assumed to be virtually complete by the age of twenty. Central nervous system manifestations of CD were emphasized only recently and include megalencephaly, epilepsy and dysplastic gangliocytomas of the cerebellum (Lhermitte-Duclos disease, LDD). Early diagnosis is important since female patients with CD are at risk of developing breast cancer. Other lesions include benign and malignant disease of the thyroid, intestinal polyps and genitourinary abnormalities. To localize the gene for CD, an autosomal genome scan was performed. A total of 12 families were examined, resulting in a maximum lod score of 8.92 at theta = 0.02 with the marker D10S573 located on chromosome 10q22-23.

Two-locus linkage analysis of cutaneous malignant melanoma/dysplastic nevi

Previous linkage analyses of 19 cutaneous malignant melanoma/dysplastic nevi (CMM/DN) kindreds showed significant evidence of linkage and heterogeneity to both chromosomes 1p and 9p. Five kindreds also showed evidence of linkage (Z>0.7) to both regions. To further examine these findings, we conducted two-trait-locus, two-marker-locus linkage analysis. We examined one homogeneity and one heterogeneity single-locus model (SL-Hom and SL-Het), and two-locus (2L) models: an epistatic model (Ep), in which CMM was treated as a genuine 2L disease, and a heterogeneity model (Het), in which CMM could result from disease alleles at either locus. Both loci were modeled as autosomal dominant. The LOD scores for CMM alone were highest using the SL-Het model (Z = 8.48, theta = .0). There was much stronger evidence of linkage to chromosome 9p than to 1p for CMM alone; the LOD scores were approximately two times greater on 9p than on 1p. The change in LOD scores from an evaluation of CMM alone to CMM/DN suggested that a chromosome 1p locus (or loci) contributed to both CMM and CMM/DN, whereas a 9p locus contributed more to CMM alone. For both 2L models, the LOD scores from 1p were greater for CMM/DN than for CMM alone (Ep: Z=4.63 vs. 3.83; Het: 4.94 vs. 3.80, respectively). In contrast, for 9p, the LOD scores were substantially lower with CMM/DN than with CMM alone (Ep: 4.64 vs. 7.06; Het: 5.38 vs. 7.99, respectively). After conditioning on linkage to the other locus, only the 9p locus consistently showed significant evidence for linkage to CMM alone. Thus, the application of 2L models may be useful to help unravel the complexities of familial melanoma.

Increased risk of pancreatic cancer in melanoma-prone kindreds with p16INK4 mutations

BACKGROUND

A gene on chromosome 9p, p16INK4, has been implicated in the pathogenesis of cutaneous malignant melanoma in 19 melanoma-prone families. In 10 of these kindreds mutations that impaired the function of the p16INK4 protein (p16M alleles) cosegregated with the disease. By contrast, in the other nine kindreds the mutation did not alter the function of p16INK4 (p16W alleles). We looked for differences in clinical and genetic epidemiologic features in these two groups of families.

METHODS

We compared the median ages at diagnosis of melanoma, number of melanomas, thickness of the tumors, and number of nevi in the kindreds. We estimated prospectively the risks of melanoma or other cancers in families followed for 6 to 18 years and the risks of other cancers since 1925 (the entire period) by comparing the number of cancer cases observed with the number expected.

RESULTS

The risk of invasive melanoma was increased by a factor of 75 in kindreds with p16M alleles and a factor of 38 in kindreds with p16W alleles. Although this difference was not significant (P = 0.14), there was a striking difference in the risk of other tumors. In kindreds with p16M alleles, the risk of pancreatic cancer was increased by a factor of 13 in the prospective period (2 cases observed, 0.15 expected; standardized incidence ratio, 13.1; 95 percent confidence interval, 1.5 to 47.4) and by a factor of 22 in the entire period (7 cases observed, 0.32 expected; standardized incidence ratio, 21.8; 95 percent confidence interval, 8.7 to 44.8). In contrast, we found no cases of pancreatic cancer in kindred with p16W alleles.

CONCLUSIONS

The development of pancreatic cancer in kindreds prone to melanoma may require a p16M mutation. Genetic factors, such as the kind of mutation found in p16INK4, may explain the inconsistent occurrence of other cancers in these kindreds.

Prospectives for cutaneous malignant melanoma. Considerations of the precursor state and heritability

Each of the discoveries through the years has begotten a series of Gordian knots. We must patiently inspect our new collection of mysteries and focus on those where our efforts may well change the course of the disease to the benefit of affected patients. The proper management of the precursor state, the beginning of the disease, and the patient exploration of the complexities of heritability would seem to be appropriate beginnings.

Genetic epidemiology of familial melanoma

Genetic epidemiology focuses on the role of genetic factors and their interaction with environmental factors in the occurrence of disease. Approximately 8% to 12% of malignant melanoma cases occur in individuals with a familial predisposition. To date, loci on chromosomes 1p and 9p have been implicated in the development of familial melanoma. Genetic epidemiologic techniques provide tools to study the heterogeneity of familial melanoma and to examine the interaction between genetic and nongenetic components of melanoma. Management of high-risk individuals from melanoma-prone families should aim to prevent disease by reducing exposure to known and suspected risk factors and to detect early melanoma by recognizing and performing biopsies on suspicious-looking nevi.

Mutations associated with familial melanoma impair p16INK4 function

Cell division is controlled by a series of positive and negative regulators which act at sequential points throughout the cell cycle. Disturbance of these checks could contribute to cancer by allowing excessive cell proliferation. The point in G1 at which cells irrevocably commit to DNA synthesis is controlled by protein complexes consisting of cyclin-dependent kinases (CDK4 or CDK6) and cyclins (D1, D2 or D3). These complexes are inhibited by low molecular weight proteins, such as p16INK4 (refs 1,2), p15INK4B (ref. 3) and p18 (ref. 4). Deletion or mutation of these CDK-inhibitors could lead to unchecked cell growth, suggesting that members of the p16INK4 family may be tumour suppressor genes. The recent detection of p16INK4 (MTS1) mutations in familial melanoma kindreds, many human tumour cell lines, and primary tumours is consistent with this idea. Previously, we described eight germline p16INK4 substitutions in 18 familial melanoma kindreds. Genetic analyses suggested that five mutations predisposed carriers to melanoma, whereas two missense mutations had no phenotypic effect. We now describe biochemical analyses of the missense germline mutations and a single somatic mutation detected in these families. Only the melanoma-predisposing mutants were impaired in their ability to inhibit the catalytic activity of the cyclin D1/CDK4 and cyclin D1/CDK6 complexes in vitro. Our data provide a biochemical rationale for the hypothesis that carriers of certain p16INK4 mutations are at increased risk of developing melanoma.

Hemoperitoneum due to spontaneous rupture of the umbilical vein

Portal hypertension often leads to collateralization of blood flow via variceal vessels that shunt blood from the portal to the systemic circulation. Rupture of an intra-abdominal varix is an unusual complication of portal hypertension that can lead to life-threatening hemoperitoneum. We describe a patient with portal hypertension secondary to liver cirrhosis who presented with acute intra-abdominal hemorrhage. At laparotomy, she was found to have a rupture of the umbilical vein. The vessel was ligated, and the patient recovered uneventfully. The causes of hemoperitoneum in cirrhosis are discussed, and the previously reported cases of intra-abdominal variceal bleeding are reviewed.

Parenchymal-stromal interactions in neoplasia. Theoretical considerations and observations in melanocytic neoplasia

The paper briefly reviews the reciprocal and continuous reciprocal interactions between epithelia, mesenchyme, and extracellular matrix in the development and maintenance of organismal form in multicellular organisms in the animal kingdom and describes the progressive changes in parenchymalstromal interactions in melanocytic neoplastic development and progression. In addition to the parenchymal stromal form in non-lesional skin seven different and unique stromal patterns are described. These have been termed: 1) The stroma (diff-regress) of programmed differentiation leading to lesional regression characteristic of common nevi; 2) concentric eosinophilic fibroplasia (cef), the hallmark of precursor nevi (dyplastic nevi) with and without melanocytic nuclear atypia; 3) Fibroplasia with angiogenesis (fa) commonly seen in superficial spreading melanoma without metastic competence (SSM); 4) Lamellar fibroplasia (lf) seen in precursor nevi and melanomas with and without metastatic competence; 5) Diffuse fibroplasia with angiogenesis (dfa), 6) Narrow, uniform concentric eosinophilic fibroplasia (nucef), 7) No parenchymal-stromal interaction (nopsi); the last three being seen in the heterogeneous stroma of melanomas of the superficial spreading type with metastatic competence. The changes in neoplastic stroma proceed in concert with the changes in the parenchyma characteristic of melanocytic tumor progression.

Increased risk of neuroectodermal tumors and stomach cancer in relatives of patients with Ewing's sarcoma family of tumors

BACKGROUND

Previous studies of the genetic epidemiology of Ewing's sarcoma have shown neither an increased incidence nor a distinct pattern of cancers in family members of Ewing's sarcoma patients.

PURPOSE

Because of a new biologic and cytogenetic classification of Ewing's sarcoma family of tumors, we wanted to reinvestigate the incidence and distribution of cancers in relatives of probands with Ewing's sarcoma family of tumors.

METHODS

Patients treated at the Pediatric Branch and the Radiation Oncology Branch of the National Cancer Institute between 1965 and December 1992, or their next of kin, were asked to complete a questionnaire on the history of cancer in all first- and second-degree relatives. The incidence of cancer in family members was compared with Connecticut Tumor Registry rates specific for sex, age, and 5-year calendar-year intervals. Observed/expected (O/E) ratios, 95% confidence intervals (CIs), and tests of homogeneity were calculated.

RESULTS

Four thousand six hundred seventy-eight family members with 196,640 person-years at risk entered the analysis. Overall, there was no increased risk of cancer (observed 472; O/E = 0.9; 95% CI = 0.8-1.0). However, several tumor types were found in significant excess. These tumors included stomach cancer (observed 34; O/E = 2.0; 95% CI = 1.4-2.8), melanoma (observed 23; O/E = 1.9; 95% CI = 1.2-2.8), brain tumor (observed 18; O/E = 1.9; 95% CI = 1.1-3.0), and bone cancer (observed 7; O/E = 4.2; 95% CI = 1.7-8.6). Risks of these cancers were higher among maternal than paternal relatives, but these differences were not statistically significant. There was a significant deficit of bladder cancer (observed 5; O/E = 0.2; 95% CI = 0.1-0.5) and rectal cancer (observed 0; O/E = 0.0; 95% CI = 0.0-0.1). Second-degree relatives had a significant cancer deficit (observed 389; O/E = 0.9; 95% CI = 0.8-0.95). This deficit was accounted for by the observed deficit of bladder and rectal cancer and is probably related to under-reporting or misclassification of cancer in second-degree relatives. Family members of 10 probands with second malignancies did not have an increased risk of all cancers (observed 20; O/E = 1.2; 95% CI = 0.7-1.8) but had an increased risk of both melanoma (observed 3; O/E = 7.3; 95% CI = 1.5-21.0) and breast cancer (observed 8; O/E = 3.2; 95% CI = 1.4-6.3).

CONCLUSION

Finding an increased risk of neuroectodermal tumors and stomach cancer in families of patients with Ewing's sarcoma family of tumors suggests that these tumors might share a common etiology. Further studies should try to confirm this hypothesis and to examine if genetic factors may have a role in these families by assessing the mode of inheritance and examining families with multiple affected members.

Age at diagnosis and transmission of invasive melanoma in 23 families with cutaneous malignant melanoma/dysplastic nevi

BACKGROUND

Familial melanoma patients tend to have an earlier age at first melanoma diagnosis, thinner lesions, a different histologic distribution, and a higher frequency of multiple primary melanomas than patients with nonfamilial melanoma. Previous examination of a large melanoma kindred from Texas suggested that although cutaneous malignant melanoma (CMM) was transmitted in an autosomal dominant fashion, there were sex differences in penetrance and disease expression.

PURPOSE

This study further evaluated the age at diagnosis, sex difference in penetrance and disease expression, and segregation of familial CMM.

METHODS

We evaluated the age at diagnosis and transmission of CMM in 23 U.S. white families with CMM/dysplastic nevi who had been followed 5-17 years. We estimated the median and mean ages at diagnosis of invasive melanoma for all individuals, for men and women separately, and by generation. Using the computer program BMDP1L, we also estimated the cumulative probability of an offspring developing CMM as a function of age according to whether the mother or father had melanoma. In addition, we used a life-table approach to estimate the probability that offspring of CMM parents were affected with CMM (penetrance).

RESULTS

The median age at diagnosis in the 23 kindreds (n = 106) was 33 years, substantially less than that of patients with sporadic melanomas in the U.S. white population. For females, the median age at diagnosis was 29 years; for males, it was 36 years. Nine percent of the case patients developed CMM before age 20 compared with 2% in the general population. There was little difference in the transmission pattern of melanoma between males and females in the 23 families, although sons of CMM parents had a higher risk of CMM than daughters of CMM parents. This difference was, however, based on small numbers and was not statistically significant. The penetrance estimates for CMM were high. They rose rapidly from 6% at age 18 to 85% by age 48. The median age at diagnosis of invasive melanoma decreased dramatically in successive generations; the reduction was 11-16 years per generation and was statistically significant (P < .0001).

CONCLUSIONS AND IMPLICATIONS

Although this reduction in median age at diagnosis may result partly from increased surveillance in hereditary melanoma families and the fact that individuals in the younger generations have not yet reached the highest at-risk ages for developing melanoma, the possibility of changes in melanoma risk and risk factors, genetic and/or environmental, across generations should be considered.

Familial risk in oral and pharyngeal cancer

We examined the relationship between a family history of cancer and risk of oral and pharyngeal cancer using epidemiological data from a large case-control investigation of these tumours. 487 (45.7%) of the cases and 485 (41.0%) of the controls reported cancer in a parent or a sibling. After controlling for age, race, sex, study location, respondent status and smoking and alcohol use, the OR associated with any cancer in the family was 1.1 [95% confidence interval (CI) 0.9-1.3]. Risks were non-significantly elevated among those with a history of cancers arising from the oral cavity/pharynx (OR = 1.2, 95% CI 0.7-2.3), oesophagus/larynx (OR = 1.6, 95% CI 0.7-3.8) and lung (OR = 1.2, 95% CI 0.8-1.8), with the excess risk primarily among those for whom a male relative, particularly a brother, was affected with these smoking-related cancers. In addition, an elevated risk of oral/pharynx cancer was found among those whose sisters developed other cancers (OR = 1.6, 95% CI 1.1-2.2). Subsite analyses revealed stronger elevated risks of smoking-related cancers in relatives of pharyngeal cancer cases (OR = 1.7, 95% CI 1.1-2.8) than of oral cancer patients. The data indicate that there is at most a weak familial aggregation of oral/pharynx cancers. Furthermore, since the excess familial risk of oral/pharynx cancer was associated with smoking-related cancers among male but not female relatives, it seems likely that environmental factors (notably smoking and drinking) contribute to the familial tendency observed in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Germline p16 mutations in familial melanoma

The p16 gene is located in chromosome 9p21, a region that is linked to familial melanoma and homozygously deleted in many tumour cell lines. We describe eight p16 germline substitutions (one nonsense, one splice donor site and six missense) in 13/18 familial melanoma kindreds. Six of these mutations were identified in 33/36 melanoma cases in nine families, whereas two were detected in normal controls and are not disease-related. The melanoma-specific mutations were detected in 9p21-linked, but not in 1p36-linked, families, thereby confirming previous reports of genetic heterogeneity. Functional analyses of these mutations will confirm those causally related to the development of familial melanoma.

Fine mapping of the locus for nevoid basal cell carcinoma syndrome on chromosome 9q

The nevoid basal cell carcinoma syndrome is an autosomal dominant disorder characterized primarily by multiple basal cell carcinomas, odontogenic keratocysts, and pits of the palms and soles. Tumor deletion studies and linkage analysis in Caucasians have revealed that the gene is on chromosome 9q. To further refine the location of the nevoid basal cell carcinoma syndrome locus, we tested linkage to this region in three families. Evaluation of recombinants suggested that the nevoid basal cell carcinoma syndrome locus lies in the interval defined distally by D9S127. Our data, together with existing published data defining D9S12 as a proximal flanking marker, refine the location of nevoid basal cell carcinoma syndrome to an 8.3-cM interval. Two of the families studied were African-American and show a notable variation in phenotypic expression in which affected individuals developed few skin cancers. However, despite clinical heterogeneity, our data are consistent with the hypothesis that the same locus is involved in these African-American families.

Localization of the gene for the nevoid basal cell carcinoma syndrome

The nevoid basal cell carcinoma syndrome (NBCC) is an autosomal dominant multisystem disorder characterized by multiple basal cell carcinomas, jaw cysts, pits of the palms and/or soles, ectopic calcification, and skeletal malformations. The NBCC gene has recently been mapped to chromosome 9q22.3-9q31. In order to further define the region containing the NBCC gene, we have analyzed 137 individuals from eight families for linkage, using 11 markers from the region. Eight markers showed statistically significant evidence for linkage to NBCC. Three markers (D9S180, ALDOB, and D9S173) showed no definite recombination with the disease locus. All families showed some evidence for linkage to markers in this region. On the basis of the inspection of individual recombinants and previously published information about map location, we suggest the following order for the markers: D9S119-D9S12-D9S197-D9S196-(NBCC,D9S180 -D9S173,ALDOB)-D9S109- D9S127-(D9S53,D9S29). We are currently developing YAC contigs for the most closely linked markers, to further refine the location of the NBCC gene.

Clinical findings in two African-American families with the nevoid basal cell carcinoma syndrome (NBCC)

The nevoid basal cell carcinoma syndrome (NBCC) is an autosomal dominant multisystem disorder with variable expressivity. We present the clinical findings on 11 African-American NBCC cases from 2 families and a review of the literature of NBCC in African-Americans. The 2 new families, as well as those previously reported, suggest minimal expression of the basal cell carcinomas and full expression of the other components of the syndrome. The 3 most common findings in the 11 cases were jaw cysts, palmar and/or plantar pits, and calcification of the falx cerebri. Only 44% (4/11) of these cases had one or more confirmed basal cell carcinomas. This frequency is substantially less than that observed in whites (90% with basal cell carcinomas). The relative lack of these skin tumors in African-Americans partly reflects ultraviolet radiation protection resulting from increased skin pigmentation. Future research should help identify the specific mutation(s) in blacks as well as other modifying genes and environmental exposures that may contribute to the varied manifestations of the syndrome.

Linkage of cutaneous malignant melanoma/dysplastic nevi to chromosome 9p, and evidence for genetic heterogeneity

We examined the relationship between cutaneous malignant melanoma/dysplastic nevi (CMM/DN) and chromosome 9p in 13 pedigrees with two or more living cases of invasive melanoma. We used two highly informative (CA)n repeats, D9S126 and IFNA, previously implicated in familial malignant melanoma (MLM), to conduct linkage analysis. Three analyses were performed: (1) CMM alone--all individuals without either confirmed melanoma or borderline lesions were considered unaffected (model A); (2) CMM/DN with both variable age at onset and sporadics (model B); and (3) CMM affecteds only--all individuals either without confirmed melanoma or with borderline lesions were designated "unknown" (model C). There was significant evidence for linkage to IFNA in all three models. For CMM alone, the maximum lod score (Zmax) was 4.36 at theta = .10 for model A and 3.39 at theta = .10 for model C. For CMM/DN (model B), Zmax = 3.05 at theta = .20. There was no significant evidence for linkage between CMM alone or CMM/DN and chromosome 9p marker D9S126. In addition, there was significant evidence for heterogeneity when a homogeneity test allowing for linkage to chromosome 9p or chromosome 1p or neither region was used. These results suggest that there is an MLM susceptibility locus on chromosome 9p but that familial melanoma is heterogeneous and not all families with CMM/DN are linked to a locus in this region.

Nonoperative management of blunt abdominal trauma: the role of sequential diagnostic peritoneal lavage, computed tomography, and angiography

STUDY OBJECTIVE

To determine the usefulness of sequential nonoperative diagnostic studies in the evaluation and treatment of stable patients after blunt abdominal trauma.

DESIGN AND SETTING

Retrospective review of a prospective treatment plan in a large urban Level I trauma center.

PARTICIPANTS

Fifty-two patients deemed stable after initial evaluation following blunt abdominal trauma.

INTERVENTIONS

Patients with a positive diagnostic peritoneal lavage for red blood cells underwent abdominal computed tomography (CT) scanning. If CT demonstrated a visceral injury, it was followed by diagnostic angiography. Attempts were made to treat on-going bleeding by transcatheter embolization.

RESULTS

Fifteen patients had negative CT scans and were successfully observed. In the other 37 patients, CT identified 17 liver, 16 splenic, and eight kidney injuries; eight extra-peritoneal bleeds; and one mesenteric hematoma. Six of these patients were observed. Thirty underwent diagnostic angiograms. Twelve had no active bleeding, and all were observed successfully. Seventeen underwent successful embolization of the bleeding site(s). One had injuries not controllable by embolization and required exploration. Six patients required laparotomy later in their course, but none had intra-abdominal bleeding or a missed intestinal injury. Despite being performed after diagnostic peritoneal lavage, CT missed only two injuries. There was one main complication, delayed recognition of a diaphragmatic injury. Three patients died, two from multiple organ failure and one from a pulmonary embolus; none was believed to be related to this technique. With our algorithm, 45 patients (86%) were spared laparotomy.

CONCLUSION

Diagnostic peritoneal lavage and CT are complementary when evaluating blunt abdominal trauma. Diagnostic peritoneal lavage is an effective screening tool. CT may be reserved for stable patients with a positive diagnostic peritoneal lavage to specify the organs injured. Bleeding often may be treated by embolization, limiting the rate of surgery.

Sun exposure and basal cell carcinomas in the nevoid basal cell carcinoma syndrome

BACKGROUND

Nevoid basal cell carcinoma syndrome (NBCC) is an autosomal dominant multisystem disorder. Persons with the NBCC gene have varied susceptibility to basal cell carcinoma (BCC) development.

OBJECTIVE

We examined the anatomic site-specific distribution of BCCs and the relation between sun exposure and numbers of BCCs in NBCC cases.

METHODS

A questionnaire asking about lifetime sun exposure, sun behavior habits, and number of BCCs was sent to 16 families with NBCC evaluated between 1985 and 1991. The results were compared with previously published data for the general population.

RESULTS

In the general population, 88% of all BCCs in women and 86% in men occurred on the face, head, neck, and arms versus 59% in women with NBCC and 65% in men with NBCC. Of BCCs in the general population 9% and 12% occurred on the trunk versus 38% and 32% of BCCs in NBCC cases, in women and men, respectively. We did not observe a strong relation between numbers of BCCs and history of lifetime sun exposure.

CONCLUSION

The anatomic-site distribution of BCCs suggests that frequent sun exposure may not be essential for the development of BCCs in patients with NBCC. However, the observation that there are more tumors on sun-exposed areas suggests that exposure to the sun promotes the development of BCCs in patients with NBCC.

Thrombocytopenia following administration of phenytoin, dexamethasone and cimetidine: a case report and a potential mechanism

Cimetidine and phenytoin are useful medications often used together in patients with seizure disorders secondary to brain masses or metabolic abnormalities. We describe a case of thrombocytopenia in the setting of concurrent phenytoin, dexamethasone and cimetidine administration, and compare it with previously described cases of thrombocytopenia induced by concurrent use of phenytoin, cimetidine, and glucocorticoids. The similarities between these cases suggest mechanisms by which these agents may induce thrombocytopenia, specifically through potential downregulation of epoxide hydrolase by glucocorticoids.