The phospholipid test of fetal respiratory maturity: its value in clinical obstetrics

CYLD-mutant cylindroma-like basaloid carcinoma of the anus: a genetically and morphologically distinct class of HPV-related anal carcinoma

Rare reports of anal carcinoma (AC) describe histologic resemblance to cutaneous cylindroma, but mutations in the tumor suppressor CYLD, the gene responsible for familial and sporadic cylindromas, have not been systematically investigated in AC. Here, we investigate CYLD-mutant AC, focusing on molecular correlates of distinct histopathology. Comprehensive genomic profiling (hybrid-capture-based DNA sequencing) was performed on 574 ACs, of which 75 unique cases (13%) harbored a CYLD mutation. Clinical data, pathology reports, and histopathology were reviewed for each CYLD-mutant case. The spectrum of CYLD mutations included truncating (n = 50; 67%), homozygous deletion (n = 10; 13%), missense (n = 16; 21%), and splice-site (n = 3; 4%) events. Compared with CYLD-wildtype AC (n = 499), CYLD-mutant ACs were significantly enriched for females (88% vs. 67%, p = 0.0001), slightly younger (median age 59 vs. 61 years, p = 0.047), and included near-universal detection of high-risk HPV sequences (97% vs. 88%, p = 0.014), predominantly HPV16 (96%). The CYLD-mutant cohort also showed significantly lower tumor mutational burden (TMB; median 2.6 vs. 5.2 mut/Mb, p < 0.00001) and less frequent alterations in PIK3CA (13% vs. 31%, p = 0.0015). On histopathologic examination, 73% of CYLD-mutant AC (55/75 cases) showed a striking cylindroma-like histomorphology, composed of aggregates of basaloid cells surrounded by thickened basement membranes and containing characteristic hyaline globules, while only 8% of CYLD-wildtype tumors (n = 34/409) contained cylindroma-like hyaline globules (p < 0.0001). CYLD-mutant carcinomas with cylindroma-like histomorphology (n = 55) showed significantly lower TMB compared with CYLD-mutant cases showing basaloid histology without the distinctive hyaline globules (n = 14) (median 1.7 vs. 4.4 mut/Mb, p = 0.0058). Only five CYLD-mutant cases (7%) showed nonbasaloid conventional squamous cell carcinoma histology (median TMB = 5.2 mut/Mb), and a single CYLD-mutant case showed transitional cell carcinoma-like histology. Within our cohort of ACs, CYLD mutations characterize a surprisingly large subset (13%), with distinct clinical and genomic features and, predominantly, a striking cylindroma-like histopathology, representing a genotype-phenotype correlation which may assist in classification of AC.

Methods of evaluating fetal lung maturity

Respiratory distress syndrome occurs in infants born with immature lungs. The immature fetal lung lacks an adequate supply of surfactant, a phospholipid-rich substance which is produced in the type II cells of the alveolar epithelium. In the fetus, surfactant is secreted into the potential air spaces of the lung and passes into the amniotic fluid as gestation proceeds. It is now clear that most methods currently in use for assessing fetal lung maturity depend on the detection of a sudden release of surfactant into the amniotic fluid as the lung reaches a critical stage of maturity. These methods, which include the lecithin/sphingomyelin ratio, the lung profile, total phospholipid or lecithin concentration, fluorescence depolarization, lamellar body phospholipid concentration, and the "shake" test, are reviewed in the light of recent understanding of the nature of surfactant. In assessing each method, we have examined possible sources of error in performing the test in the laboratory, factors which could theoretically limit its ability to reflect the state of fetal lung maturity and current information regarding its reliability, in terms of clinical performance. Guidelines for future research in this area are also suggested.

Respiratory distress syndrome with mature lecithin/sphingomyelin ratios: diabetes mellitus and low Apgar scores

A detailed study was made of 150 women delivered of their infants within 72 hours of an amniocentesis where the lecithin/sphingomyelin (L/S) ratio was 2.0 or greater. There were nine neonates with respiratory distress (6.0 per cent). There were two neonatal deaths, both due to severe congenital heart disease. A mature amniotic fluid L/S ratio predicts a newborn infant who will not have respiratory distress syndrome (RDS) in most pregnancies. There is a significantly increased risk of RDS in neonates with a mature L/S ratio if the mother has insulin-dependent diabetes or if there is a resulting low Apgar score. The method of delivery (cesarean section or vaginal) does not affect the frequency of RDS where the L/S ratio is 2.0 or more.