Pallister–Killian Syndrome versus Trisomy 12p—A Clinical Study of 5 New Cases and a Literature Review

Pallister–Killian syndrome (PKS) is a rare, sporadic disorder defined by a characteristic dysmorphic face, pigmentary skin anomalies, intellectual disability, hypotonia, and seizures caused by 12p tetrasomy due to an extra isochromosome 12p. We present three cases of PKS and two cases of trisomy 12p to illustrate and discuss features rarely cited in the literature, present certain particularities that not yet been cited, and analyze the differences between entities. Moreover, we present alternative methods of diagnosis that could be easily used in daily practice. Features not yet or rarely reported in PKS literature include marked excess of hair on the forehead and ears in the first months of life, a particular eye disorder (abnormal iris color with pointed pupil), connective tissue defects, repeated episodes of infection and autonomic dysfunction, endocrine malfunction as a possible cause of postnatal growth deficit, more complex sensory impairments, and mild early myoclonic jerks. After performing different combinations of tests, we conclude that MLPA (follow-up kit P230-B1) or array CGH using DNA extracted from a buccal swab is a reliable method of diagnosis in PKS and we recommend either one as a first intention diagnostic test. In cases without major defects associated (suspicion trisomy 12p), subtelomeric MLPA should be performed first.

Primary Testicular Neuroendocrine Tumor Coexisting With Seminoma Sharing Germ Cell Origin

A 40-year-old, male, Japanese patient presented with the complaint of painless, right testicular swelling. Tumor markers for testicular cancer were normal. He underwent radical orchiectomy with the clinical diagnosis of stage I seminoma. Pathological examination revealed seminoma and coexisting neuroendocrine tumor (NET). Germ cell neoplasia in situ (GCNIS) was present in the vicinity of seminoma, but there was no continuity between NET and seminoma. Tumor cells of both lesions displayed amplification of 12p and isochromosome 12p on fluorescence in situ hybridization, suggesting that both tumors originated from GCNIS. The present report is the first to describe a case of primary testicular NET coexisting with seminoma in an ipsilateral testis.

Mediastinal Germ Cell Tumor and Acute Megakaryoblastic Leukemia With Co-occurring KRAS Mutation and Complex Cytogenetics

Young males have a unique but rare predilection to develop mediastinal nonseminomatous germ cell tumors (NSGCTs) and concomitant acute megakaryoblastic leukemia (AMKL). Common cytogenetic and molecular abnormalities such as isochromosome 12p and somatic Tumor Protein P53(TP53) and Phosphatase And Tensin Homolog (PTEN) mutations have been reported in the presumed mutual neoplastic clones of origin. We report the case of a 17-year-old male who presented with a mediastinal NSGCT with high-grade sarcomatous transformation and a diagnosis of AMKL approximately 4 months later. Next-generation sequencing revealed identical KRAS Proto-Oncogene, GTPase (KRAS) p.Ala146Thr, TP53 p.Leu257Pro, and PTEN p.Leu181Pro missense mutations at similar variant allele frequencies in both the NSGCT and AMKL samples. Cytogenetic and microarray analyses detected shared copy gains in all chromosomes except chromosomes 9, 13, and Y. Multiple additional clonal chromosomal alterations were detected in the AMKL sample when compared with the NSGCT. This case emphasizes the shared clonal origins of these malignancies and identifies KRAS and other copy number alterations as potential molecular drivers in a subset of these combined diseases.

Bifid cardiac apex in Pallister-Killian syndrome

Aim: Pallister-Killian syndrome (PKS) is a rare chromosomal disorder, caused by tissue-limited mosaicism for an isochromosome 12p. Prenatal diagnosis of PKS is generally incidental. Although clinical presentation of PKS varies, cytogenetic findings are constant, and include a tetrasomy of chromosome 12p. We report a case of prenatally diagnosed PKS with unique dysmorphic feature: bifid cardiac apex, a type of morphology that has not been documented before. Case presentation: Our patient was the 38-year-old pregnant woman who underwent amniocentesis. Cytogenetic analysis of amniotic fluid detected a mosaic karyotype with a supernumerary chromosome (SMC) in 64 % of fetal amniocytes. To determine the chromosomal origin of SMC, fluorescence in situ hybridization was performed and tetrasomy 12p was confirmed: mos 47,XY,+mar[18]/46,XY[10].ishi(12p)(8M16/SP6++,CEP12+,VIJyRM2196-). Ultrasound examination showed a fetus with cleft lip, echogenic focus in the left ventricle of the heart and shortened fetal long bones. After receiving a genetic counseling for PKS, the woman requested a termination of pregnancy. A postmortem inspection of the fetus revealed a complex heart anomaly that includes bifid cardiac apex and ventricular septal defect. Conclusions: This report expands the clinical manifestations of PKS with a unique feature of bifid cardiac apex, and highlights the targeted prenatal diagnosis of PKS if specific ultrasound markers are present.

A unique uterine cervical “teratocarcinosarcoma”: a case report

Background Teratocarcinosarcoma (TCS) is a rare aggressive tumor of the nasal cavity and paranasal sinuses and has both epithelial and two or more mesenchymal components. In other organs, 5 cases of ovarian tumors closely resembling TCS have been reported; however, there has been no published case of cervical TCS. Herein, we describe a unique case of cervical tumor that had carcinosarcomatous and teratomatous features, resembling a sinonasal TCS. Case presentation A 45-year-old woman presented to our hospital for evaluation of a cervical lesion. The gynecologist found a large polypoid mass, whose biopsy showed glandular components of probable germ cell origin based on the immunohistochemical features. The patient underwent total hysterectomy with bilateral salpingo-oophorectomy. The cervical polypoid mass was found to consist of both epithelial and mesenchymal tissues, including immature glandular structure resembling fetal enteric tubules, neuroepithelial cells, hyaline cartilage, and rhabdomyosarcoma cells. This tumor was diagnosed as TCS of the uterine cervix. Following the surgery, the patient received radiotherapy and has been free of disease for 13 months. Conclusion This is the first case report of cervical TCS. The tumor is thought to be histogenetically less associated with HPV infection, and its teratomatous components with an absence of cytogenetic abnormalities (including isochromosome 12p (i(12p)) suggest a analogous histogenesis compared to pure mature or immature teratoma.

Clinicopathologic Features and Chromosome 12p Status of Pediatric Sacrococcygeal Teratomas: A Multi-institutional Analysis

Chromosome 12p gains are typically present in postpubertal male patients with testicular malignant germ cell tumors, including most teratomas, and absent in pure ovarian teratomas, both mature and immature. We sought to evaluate the clinicopathologic features and chromosome 12p status of pediatric patients with sacrococcygeal teratomas (SCTs) using the institutional databases of 2 tertiary medical centers. Seven mature teratomas (3 pure, 2 with yolk sac tumor, 1 with medulloepithelioma, and 1 with ependymoma) and 3 immature teratomas (2 pure: grade 2 and grade 3 and 1 mixed: grade 3 with yolk sac tumor) were identified. All patients underwent surgery and 2 received adjuvant chemotherapy. Fluorescence in situ hybridization analysis was performed to elucidate chromosome 12p gains, including isochromosome 12p. All 10 tumors analyzed lacked 12p gains regardless of the components. No patient had evidence of disease at their most recent interval follow-up (mean: 30, range: 7–91 months), irrespective of margin status or of receiving chemotherapy. Overall, our study suggests an absence of chromosome 12p abnormalities in clinically nonaggressive SCTs. Additional data are required to confirm these findings before definitive patient care recommendations can be made.

Report of new case of Pallister – Killian syndrome in fetus

Pallister — Killian syndrome (PKS) is a sporadic chromosomal anomaly caused by a tissue-specific mosaic distribution of an additional isochromosome 12p. A case of second trimester fetus with PKS is presented. Antenatal ultrasound examination showed left diaphragmatic hernia. Standard cytogenetic analysis of cultured amniocytes supposed mosaic tetrasomy 12p: 46,XY/ 47,XY,+?i(12p). Fluorescent in situ hybridization (FISH) was used to confirm the nature of the additional chromosome. Pathological examination confirmed prenatal diagnosis.