Clinical outcomes of fetuses with cardiac rhabdomyoma: A case series from a tertiary center.

AIMS: The study aims to evaluate the genetic and clinical outcomes of fetal cardiac rhabdomyoma in our tertiary center. METHODS: Data of cases with cardiac rhabdomyoma detected by fetal echocardiography during antenatal follow-up were analyzed retrospectively. RESULTS: Nine cases were included in the study. The incidence of cardiac rhabdomyoma was 0.003%. The median fetal diagnosis time was 26th weeks, the most common location was the LV. There was no hemodynamic disorder requiring cardiovascular intervention in any of the cases. Of the eight genetically tested cases, four were tuberous sclerosis complex (TSC) gene-negative, one hereditary TSC2, one de novo TSC1, and two de novo TSC2 gene mutants. Postnatal first-year survival rate of the cases was 88.8%. CONCLUSIONS: Cardiac rhabdomyoma is a rare fetal and pediatric pathology that generally is a remarkable finding in the clinical process of TSC. Therefore, cases should be evaluated multisystemically and genetic counseling should be given to the family.

Three-Year Follow-Up after Intrauterine mTOR Inhibitor Administration for Fetus with TSC-Associated Rhabdomyoma.

Tuberous sclerosis complex (TSC) is a multisystem disorder characterized by seizures, neuropsychiatric disorders, and tumors of the heart, brain, skin, lungs, and kidneys. We present a three-year follow-up of a patient with TSC-associated rhabdomyoma detected in utero. Genetic examination of the fetus and the parents revealed a de novo variant in the TSC2 gene (c.3037delG, p.Asp1013IlefsTer3). Oral everolimus was initiated in the pregnant mother to regress the fetal tumor, which was successful. To the best of our knowledge, there is very little information regarding the use of everolimus therapy during pregnancy. West-syndrome was diagnosed when the proband was four months old. The symptoms were well-manageable, however temporarily. Therapy-resistant focal seizures were frequent. The patient had good vitals and was under regular cardiological control, showed a balanced circulation, and did not require any medication. Subependymal giant cell astrocytoma (SEGA) identified by regular neuroimaging examinations remained unchanged, which may be a consequence of early intrauterine treatment. Early detection of the pathogenic TSC2 variant, followed by in utero administration of everolimus and early vigabatrin therapy, allowed the detection of a milder developmental delay of the proband. Our study emphasizes how early genetic testing and management of epilepsy are pivotal for proper neurodevelopmental impacts and therapeutic strategies.

Study on prenatal diagnosis and pregnancy outcome analysis of fetuses with cardiac rhabdomyoma.

OBJECTIVE: To investigate the prenatal imaging characteristics, genetic characteristics and pregnancy outcome of fetuses with cardiac rhabdomyoma. STUDY DESIGN: The prenatal ultrasound, cranial MRI imaging information and genetic test results of 35 fetuses prenatally diagnosed with cardiac rhabdomyoma were collected and retrospectively analyzed, and the pregnancy outcome was followed up. RESULT: Cardiac rhabdomyomas mainly occurred in left ventricular wall and ventricular septum; cranial MRI imaging was found abnormal in 38.1% (8/21) of the fetuses; genetic test was found abnormal in 58.82% (10/17) of the fetuses; the fetus was born in 12 cases and the pregnancy was terminated in 23 cases. CONCLUSION: TRIO whole exome sequencing (TrioWES) is recommended as the genetic test regime for cardiac rhabdomyoma. The comprehensive evaluation of prognosis of fetuses needs to consider the genetic results and whether the brain is involved; the prognosis of fetuses with simple cardiac rhabdomyoma is good.

A case of massive fetal cardiac rhabdomyoma: ultrasound features and management.

We report the case of a massive fetal cardiac rhabdomyoma recently occurred at our clinic. A woman at 23 weeks of gestational age was referred to our center for a fetal cardiac echogenic mass of 26 mm detected at the second-trimester screening ultrasound. During pregnancy, though, the mass progressively increased its dimensions until reaching 48 mm in diameter at 37 weeks of gestation. Fetal echoencephalography and brain magnetic resonance did not show any further fetal anomalies, but molecular genetic testing at amniocentesis revealed a heterozygotic missense variant of gene TSC2 associated with Tuberous Sclerosis. The mass was therefore most likely preferable to a single large rhabdomyoma of gradually increasing dimensions. The baby was delivered at term with a cesarean section. Because of the rhabdomyoma remarkable size and newborn ECG electrical alterations, postnatal therapies with Flecainide and Everolimus were started. Everolimus treatment led to a significant and progressive reduction in the cardiac mass volume. This case, therefore, shows the efficacy of what seems to be a promising treatment in pediatric patients with large rhabdomyomas.Learning points:Rhabdomyomas may present with different features: most often they appear as multiple masses along the interventricular sept, but they may also appear as a single large thoracic mass.When a rhabdomyoma is suspected, genetic counseling is recommended.Both before and after birth, a multidisciplinary approach is useful to choose the appropriate therapy for the newborn.mTOR inhibitors therapies look like promising therapeutic approaches to stimulate the involution of rhabdomyomas.

Genotype/phenotype correlation in 123 Chinese patients with Tuberous Sclerosis Complex.

Tuberous Sclerosis Complex (TSC) is a multisystemic neurocutaneous disorder with autosomal dominant inheritance. We performed mutation analyses on 123 Chinese patients with "definite TSC" according to the latest diagnostic criteria. Pathogenic / likely-pathogenic variants were identified in 72.2% of all index patients (70/97), in which 35.7% (25/70) had TSC1 variants and 64.3% (45/70) had TSC2 variants. 84.5% (82/97) cases were sporadic and 15.5% (15/97) cases were familial. 62 unique variants were reported, in which 41.9% (26/62) were novel. Male patients had significantly more subependymal nodules (p=0.029) than females, whereas renal angiomyolipoma (p=0.032) occurred predominantly in females. Sporadic cases also had more renal angiomyolipoma (p=0.004), cortical tubers (p=0.008), hypopigmented macules (p=0.018) and fibrous cephalic plaques (p=0.028) than cases with known inheritance. Patients with TSC2 pathogenic variants were more likely to have mental retardation (p<0.001), cardiac rhabdomyoma (p=0.004), renal angiomyolipoma (p=0.006) and facial angiofibromas (p=0.026) than those with TSC1 pathogenic variants, while mutation-negative cases showed a mixed phenotype between those with TSC1 and TSC2 variants. There were no significant phenotypic differences between patients with and without TSC1/TSC2 variants, but TSC2 missense and in-frame variants were associated with higher frequencies of mental retardation (P<0.001), renal angiomyolipoma (p=0.001), cardiac rhabdomyoma (p=0.012) and facial angiofibroma (p=0.021) than those with TSC1 frameshift and splice site variants. Furthermore, a higher frequency of mental retardation (p=0.013) was observed in patients with TSC2 missense and in-frame variants than those with frameshift and splice site variants. All 14 antenatal-onset patients had cardiac rhabdomyoma. They had fewer seizures (p=0.028) than patients with paediatric-onset, but were more likely to have mental retardation (p=0.035) than individuals with adult-onset disease. Generally, paediatric-onset patients had more neurological manifestations, while initial presentations of adult-onset TSC were more diverse.

Molecular assessment of paratesticular rhabdomyomas demonstrates recurrent findings, including a novel H3C2 p.K37I mutation.

Rhabdomyomas are benign tumors with skeletal muscle differentiation that are broadly divided into cardiac and extracardiac types. The latter demonstrate a predilection for head and neck and genital locations and are further subclassified into adult-type rhabdomyoma (ATRM), fetal-type rhabdomyoma (FTRM) and genital rhabdomyoma (GRM). Most extracardiac rhabdomyomas that arise in paratesticular tissues have a somewhat distinctive morphology and have been termed sclerosing rhabdomyomas (SRM). Therefore, we hypothesized that these tumors may harbor recurrent genetic alterations. In this study, we assessed 15 paratesticular rhabdomyomas (11 initially classified as SRM, 2 cellular FTRM and 2 ATRM) using massively parallel DNA and RNA sequencing. Five of 14 successfully sequenced cases harbored a novel H3C2 p.K37I mutation (4 SRM and 1 ATRM). This mutation replaced a highly conserved lysine residue that is a target for epigenetic modifications and plays a role in regulation of DNA replication. Moreover, 4 tumors (2 cellular FTRM, 1 case initially diagnosed as SRM and 1 ATRM) had complex copy number profiles characterized by numerous chromosome-level and arm-level copy number gains, consistent with a ploidy shift. Rereview of the SRM with copy number gains demonstrated that it was significantly more cellular and had a more prominent fascicular architecture than the rest of the SRMs included in this series. Therefore, it was retrospectively reclassified as a cellular FTRM. In conclusion, this study demonstrated that paratesticular rhabdomyomas harbor recurrent somatic H3C2 p.K37I mutations and ploidy shifts.

Prenatal MR Imaging Phenotype of Fetuses with Tuberous Sclerosis: An Institutional Case Series and Literature Review.

BACKGROUND AND PURPOSE: Most patients with tuberous sclerosis complex (TSC) do not receive prenatal diagnosis. Our aim was to describe MR imaging findings to determine the following: 1. Whether normal fetal MR imaging is more common in fetuses imaged at ≤24 weeks' gestation compared with >24 weeks 2. The frequency of cardiac rhabdomyoma 3. The range of MR imaging phenotypes in fetal tuberous sclerosis complex. MATERIALS AND METHODS: Our institutional fetal MR imaging data base was searched between January 1, 2011 and June 30, 2021, for cases of TSC confirmed either by genetic testing, postnatal imaging, postmortem examination, or composite prenatal imaging findings and family history. A MEDLINE search was performed on June 8, 2021. RESULTS: Forty-seven published cases and 4 of our own cases were identified. Normal findings on fetal MR imaging were seen at a lower gestational age (mean, 24.7 [SD, 4.5 ] weeks) than abnormal findings on MR imaging (mean, 30.0 [SD, 5.3] weeks) (P = .008). Nine of 42 patients with abnormal MR imaging findings were ≤24 weeks' gestation. Subependymal nodules were present in 26/45 cases (57.8%), and cortical/subcortical lesions, in 17/46 (37.0%). A foramen of Monro nodule was present in 15 cases; in 2/7 cases in which this was unilateral, it was the only abnormal cerebral finding. Cardiac rhabdomyoma was absent in 3/48 cases at the time of fetal MR imaging but was discovered later. Megalencephaly or hemimegalencephaly was observed in 3 cases. CONCLUSIONS: Fetuses with abnormal cranial MR imaging findings were older than those with negative findings. Fetal hemimegalencephaly and megalencephaly should prompt fetal echocardiography. Cardiac rhabdomyoma was not always present at the time of fetal MR imaging.

Prostatic Rhabdomyoma in a Toddler: A Case Report With Molecular Characterization.

We present a 29-month-old male patient in follow-up due to pyelocaliceal dilation with a prostatic nodule incidentally found during ultrasound evaluation. Cysto video endoscopy was performed and a prostate biopsy, obtained. Microscopic evaluation showed a haphazardly distributed population of muscular cells with cross striations without evidence of mitosis or necrosis. Immunohistochemistry was positive for myogenin and desmin and negative for smooth muscle actin. Next generation sequencing was performed without finding any pathogenic variant or fusion in the tumor RNA. The patient received no further treatment, remained asymptomatic and continues in follow up, 3 years after initial diagnosis. We report a case of prostate rhabdomyoma in a toddler, an exceptional location that raises concern about differential diagnosis with its malignant counterpart, rhabdomyosarcoma, especially at this age.

Detection of TSC1/TSC2 mosaic variants in patients with cardiac rhabdomyoma and tuberous sclerosis complex by hybrid-capture next-generation sequencing.

BACKGROUND: Fetal cardiac rhabdomyoma (CR) is strongly associated with tuberous sclerosis complex (TSC), which is caused by variants in TSC1 and TSC2. However, in 10%-15% of patients with clinically confirmed TSC, no TSC1/TSC2 variants are identified by panel sequencing or multiplex ligation-dependent probe amplification (MLPA). METHODS: We analyzed eight fetuses with CR and their families. No TSC1/TSC2 variants had previously been identified for six of these fetuses, and we suspected the other two families of gonadal mosaicism. We performed next-generation sequencing (NGS) using CR tissue, umbilical cord tissue, and parental blood. All positive results, involving two paternal semen, were verified by droplet digital polymerase chain reaction (ddPCR). RESULTS: Four fetuses carried low-level mosaic variants (0.05%-14.89%), and two only exhibited somatic mosaic variants in the CR tissue (15.76% and 37.69%). Two fathers had gonadal mosaicism (9.07% and 4.86%). We identified nine pathogenic variants in eight fetuses, including one fetus with a second-hit variant. CONCLUSION: The fetuses assessed in this study carried low-level and somatic mosaic variants, and CR tissue from one fetus exhibited a second-hit variant. Heterozygous gonadal variants can exist in patients with low-level mosaicism. Combining NGS with ddPCR improves the accuracy of prenatal TSC diagnosis.

[Tuberous sclerosis complex: analysis of areas of involvement, treatment progress and translation to routine clinical practice in a cohort of paediatric patients]. / Complejo esclerosis tuberosa: análisis de los ámbitos de afectación, progreso en el tratamiento y traslación a la práctica clínica habitual en una cohorte de pacientes pediátricos.

INTRODUCTION: Tuberous sclerosis complex (TSC) displays great phenotypic variability. Increasingly early diagnosis, including prenatal identification, entails the need for the paediatrician and neuropaediatrician to establish early suspicion and identification of factors that may influence prognosis and treatment. AIM: To determine the clinical criteria for early diagnosis, initial complementary tests, actions and treatments to prevent different comorbidities, so as to improve the prognosis of these patients. PATIENTS AND METHODS: Descriptive, retrospective study of = 18-year-olds with a definitive diagnosis of TSC in a tertiary hospital from 1998 to 2019. We collected variables referring to epidemiological data, multisystem involvement, complementary tests and genetics. RESULTS: Ninety-four patients were analysed. The main diagnostic reasons were epilepsy and rhabdomyomas. The frequency of occurrence of clinical criteria was determined, and neuropathological findings were the main findings, followed by cutaneous stigmata, rhabdomyomas and renal lesions. Statistical relationships were found between clinical, radiological and genetic aspects, the influence of preventive activities on the occurrence of epilepsy and the relevance of everolimus use were tested. CONCLUSIONS: Rhabdomyomas and skin stigmata in patients and parents are major diagnostic signs in infants. Tubers and subependymal nodules are statistically associated with the development of epilepsy. Early epileptic spasms, refractory to treatment in the first months, increase the risk of cognitive deficits and autism spectrum disorder. Epileptic abnormalities need to be closely monitored in the first year of life. Everolimus is an alternative treatment for several comorbidities, but its early use (< 3 years) requires further study.

TITLE: Complejo esclerosis tuberosa: análisis de los ámbitos de afectación, progreso en el tratamiento y traslación a la práctica clínica habitual en una cohorte de pacientes pediátricos.Introducción. El complejo esclerosis tuberosa (CET) presenta gran variabilidad fenotípica. El diagnóstico cada vez más precoz, incluyendo la identificación prenatal, conlleva la necesidad de establecer una sospecha e identificación temprana, por parte del pediatra y del neuropediatra, de factores que pueden influir en su pronóstico y tratamiento. Objetivo. Determinar los criterios clínicos de un diagnóstico precoz, las pruebas complementarias iniciales, las actuaciones y los tratamientos que prevengan diferentes comorbilidades, mejorando el pronóstico de estos pacientes. Pacientes y métodos. Estudio descriptivo, retrospectivo de = 18 años con diagnóstico definitivo de CET en un hospital terciario desde 1998 hasta 2019. Se recogieron variables epidemiológicas, de afectación multisistémica, pruebas complementarias y genética. Resultados. Se analizó a 94 pacientes. Los principales motivos diagnósticos fueron la epilepsia y los rabdomiomas. Se determinó la frecuencia de aparición de los criterios clínicos, y los hallazgos neuropatológicos fueron los principales, seguidos de los estigmas cutáneos, los rabdomiomas y las lesiones renales. Se comprobaron relaciones estadísticas entre aspectos clínicos, radiológicos, genéticos, la influencia de las actividades preventivas sobre la aparición de epilepsia y la relevancia del uso de everolimús. Conclusiones. Los rabdomiomas y los estigmas cutáneos en pacientes y progenitores constituyen signos diagnósticos principales en lactantes. Los túberes y los nódulos subependimarios tienen asociación estadística con el desarrollo de epilepsia. Los espasmos epilépticos en edades precoces, refractarios a tratamiento en los primeros meses, incrementan el riesgo de déficit cognitivo y trastorno del espectro autista. Es necesario monitorizar estrechamente las anomalías epilépticas en el primer año de vida. El everolimús supone una alternativa de tratamiento en varias comorbilidades, pero su uso precoz (menor de 3 años) precisa más estudios.

Clinical, cellular, and molecular characterisation of cardiac rhabdomyoma in tuberous sclerosis.

BACKGROUND: Rhabdomyoma is the most common cardiac tumour in children. It is usually associated with tuberous sclerosis complex caused by mutations in TSC-1 or TSC-2 genes. This tumour typically regresses by unknown mechanisms; however, it may cause inflow or outflow obstruction that necessitates urgent surgery. Here we investigate the clinical features and the genetic analysis of patients with tuberous sclerosis complex presenting with large rhabdomyoma tumours. We also investigate the potential role of autophagy and apoptosis in the pathogenesis of this tumour. METHODS: All the patients with cardiac rhabdomyoma referred to Aswan Heart Centre from 2010 to 2018 were included in this study. Sanger sequencing was performed for coding exons and the flanking intronic regions of TSC1 and TSC2 genes. Histopathological evaluation, immunohistochemistry, and western blotting were performed with P62, LC3b, caspase3, and caspase7, to evaluate autophagic and apoptotic signaling. RESULTS: Five patients were included and had the clinical features of tuberous sclerosis complex. Three patients, who were having obstructive tumours, were found to have pathogenic mutations in TSC-2. The expression of two autophagic markers, P62 and LC3b, and two apoptotic markers, caspase3 and caspase7, were increased in the tumour cells compared to normal surrounding myocardial tissue. CONCLUSION: All the patients with rhabdomyoma were diagnosed to have tuberous sclerosis complex. The patients who had pathogenic mutations in the TSC-2 gene had a severe disease form necessitating urgent intervention. We also demonstrate the potential role of autophagy and apoptosis as a possible mechanism for tumourigenesis and regression. Future studies will help in designing personalised treatment for cardiac rhabdomyoma.

TSC1 intragenic deletion transmitted from a mosaic father to two siblings with cardiac rhabdomyomas: Identification of two aberrant transcripts.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant disorder characterized by non-cancerous tumors in multiple organs including the brain, kidney, lung, heart, and skin. We encountered a Japanese family consisting of two siblings (a four-year-old boy and a one-year-old girl) with multiple cardiac rhabdomyomas conveying a high risk of TSC and apparently unaffected sibling (a two-year-old girl) and parents. Whole exome sequencing and application of Integrative Genomic Viewer revealed an identical intragenic TSC1 deletion with the breakpoints on intron 15 and exon 19 in the affected siblings, but not in the apparently unaffected sibling and parents. Subsequently, PCR-based analyses were performed using primers flanking the deletion, showing that the deletion was also present in the father and that the deletion occurred between chr9:135,777,038 (bp) and chr9:135,780,540 (bp) in association with a one bp overlap. Furthermore, RT-PCR analyses were carried out using lymphoblastoid cell lines, revealing a major in-frame insertion/deletion transcript produced by aberrant splicing using a cryptic ″ag″ splice acceptor motif at intron 15 (r.1998_2438delinsTTCATTAGGTGG) and a minor frameshift transcript generated by aberrant splicing between exon 15 and exon 20 (r.1998_2502del, p.Lys666Asnfs*15) in the affected siblings. These findings imply that the intragenic deletion producing two aberrant transcripts was generated as a somatic pathogenic variant involving the germline in the father and was transmitted to the affected siblings.

Fetal cardiac rhabdomyoma due to paternal mosaicism of TSC2: A case report.

RATIONALE: Rhabdomyoma is the most common type of fetal heart tumors and 50% to 60% of cardiac rhabdomyomas are associated with tuberous sclerosis complex (TSC). TSC is characterized by hamartomas in multiple organ systems including the brain, heart, skin, lungs, and kidneys, resulting in complications such as learning difficulties, epilepsy, behavioral problems, and renal failure. The etiological diagnosis of Rhabdomyoma is very important. PATIENT CONCERNS: A 22-year-old G2P0 woman chose to terminate the pregnancy at 24 + 4 weeks of gestation because of the presence of a cardiac space-occupying lesion in the fetus. DIAGNOSES: The pathological diagnosis of cardiac neoplasm tissue was cardiac rhabdomyoma, but the etiology was unknown. INTERVENTIONS: Targeted exome capture, next-generation sequencing (NGS) and sanger sequencing were performed on peripheral blood lymphocytes and paternal sperm. OUTCOMES: Targeted exome capture sequencing revealed a novel heterozygous variant (NM_000548, c.2294delC) in the tuberous sclerosis 2 (TSC2) gene. Sanger sequencing of maternal blood samples showed no mutation at this locus, however, suspected low level mosaicism was observed in paternal blood samples. Deep NGS analysis showed that about 7% paternal alleles from peripheral blood leucocytes and 20% paternal alleles from sperm carried the mutation consistent with somatic and germinal mosaicism. LESSONS: For fetuses suspected of TSC, when pathogenic mutations are detected in the tuberous sclerosis 1 (TSC1) or TSC2 gene, it is recommended that the parents should be screened by deep NGS and their germ cells are screened as well if necessary, which would help to predict the risk of TSC recurrence in the next pregnancy.

Cervical rhabdomyoma a rare entity: Case report with review of literature.

Genital rhabdomyomas are extremely rare benign tumors of skeletal muscle origin, majority of them being reported in vaginal location. Extensive literature search revealed only three such cases reported in cervix. We hereby report fourth such case of cervical rhabdomyoma in a 35-years-old female patient. The diagnosis was confirmed by histomorphology with desmin and myoD1 positivity on immunohistochemistry. Due to paucity of cases no definite treatment guidelines are available. Differentiation from identical and more common malignant counterpart which is rhabdomyosarcoma is essential to avoid unnecessary aggressive therapy.

Prenatal exome sequencing in fetuses with congenital heart defects.

The genetic diagnosis of congenital heart defects (CHDs) is challenging because of genetic and phenotypic heterogeneity. The aim of our study was to evaluate the clinical value of whole exome sequencing (WES) in the prenatal diagnosis of CHDs in a large cohort. Trio-based WES was performed in 260 fetuses with CHDs negative for karyotype and chromosome microarray analysis results. WES produced a diagnostic yield of 10% (26/260) in the entire cohort. Relative high diagnostic rate was observed in cases with cardiac rhabdomyoma (60%), complex CHDs (16.7%), septal defect (14.0%), and conotruncal defect (9.9%). There was no significant difference between the diagnostic yields in simple and complex CHDs groups (9.9% vs 16.7%), and in non-isolated and isolated CHDs groups (15.7% vs 7.9%). The diagnostic yields in cases with CHDs with soft markers, CHDs with fetal growth restriction, and CHDs with other structural anomalies (syndromic CHDs) were 0 (0/13), 50% (1/2) and 18.2% (10/55), respectively. Variants of unknown significance were detected in 16 (6.2%) fetuses, and secondary findings in 7 (2.7%) cases. Variants in 14 candidate genes were identified. Our study demonstrates an incremental diagnostic yield by trio-based WES in the prenatal diagnosis of CHDs after routine tests, not as high as expected.

Prenatal genetic diagnosis of cardiac rhabdomyoma: A single-center experience.

OBJECTIVE: The aim of this study is to review our institution's experience with fetal cardiac rhabdomyoma, and to document the prenatal genetic testing for tuberous sclerosis complex (TSC) and clinical outcome of the affected pregnancies. STUDY DESIGN: During a four-year period, patients with fetal cardiac rhabdomyoma were detected by echocardiography in the second trimester of pregnancy. Molecular genetic analysis was conducted on fetuses to screen for variants of TSC1/TSC2 genes. We reviewed medical records of these affected pregnancies, including maternal demographics, sonographic findings, genotyping results and pregnancy outcomes. RESULTS: Eleven cases with fetal cardiac rhabdomyoma were studied during the study period. A pathogenic variant of TSC1/TSC2 genes was detected in all cases, including two with an inherited variant and nine with a de novo variant. Out of these eleven cases diagnosed prenatally, eight pregnancies were terminated and three continued till term. CONCLUSIONS: Cardiac rhabdomyoma is the prenatal sign of TSC. A molecular investigation of TSC1/TSC2 genes should be recommended for fetuses with a rhabdomyoma and the parents, and the prognostic counselling should include TSC and its consequences.

Adult rhabdomyoma presenting as thyroid nodule on fine-needle aspiration in patient with Birt-Hogg-Dubé syndrome: Case report and literature review.

Extracardiac rhabdomyoma is an uncommon benign striated muscle tumor with a predilection for the head and neck region. However, it is extremely rare for extracardiac rhabdomyoma to present as a thyroid nodule. We report a case of rhabdomyoma diagnosed by thyroid fine-needle aspiration (FNA) in a patient with Birt-Hogg-Dubé (BHD) syndrome. A 60-year-old man with BHD syndrome presented for recurrent pneumothorax. Chest CT incidentally identified a thyroid nodule. Subsequent sonography confirmed a 4.44 × 2.28 × 2.82 cm solid, hypoechoic nodule with smooth margins in the right upper pole. Ultrasound-guided FNA revealed many clusters and scattered isolated large polygonal cells with abundant granular cytoplasm and small peripherally located nuclei. Vague striations in the cytoplasm were focally identified. No follicular cells or colloid was present. Immunocytochemistry on one direct smear slide demonstrated diffuse positivity for desmin, supporting muscular differentiation. Subsequent surgery identified an adult rhabdomyoma originating from the inferior constrictor muscle of the neck and anteriorly displacing the thyroid. Because the mass was intimately associated with the thyroid gland, it was initially mistaken for a thyroid nodule on ultrasound. Diagnosis of rhabdomyoma on FNA is challenging, especially when rhabdomyoma mimics a thyroid nodule on imaging. The differential diagnosis includes Hurthle cell neoplasm, granular cell tumor, colloid nodule, and normal striated skeletal muscle. Adequate radiologic data and familiarity with the cytologic features of rhabdomyoma are critical for an accurate diagnosis.