PTEN hamartoma of the soft tissue: the initial manifestation of an underlying PTEN hamartoma tumor syndrome in a 4-year-old female

Imaging findings of children with PTEN-related hamartoma tumor syndrome: a 20-year multicentric pediatric cohort

BACKGROUND

PTEN-related hamartoma tumor syndrome results from a mutation in the PTEN gene located at 10q23.31. This syndrome represents a spectrum of different phenotypes of variable expressions, now recognized as part of the same condition. Patients with this mutation have an increased risk of developing a wide range of findings, including malignancies. Although widely described in adults, there are no large series describing the imaging findings in patients before adulthood. Knowledge of the findings seen in children and adolescents with PTEN-related hamartoma tumor syndrome can help guide further management and improve surveillance recommendations.

OBJECTIVE

To describe the spectrum of imaging abnormalities in pediatric patients with PTEN-related hamartoma tumor syndrome.

MATERIALS AND METHODS

We performed a retrospective, cross-sectional, multicenter study conducted between January 2000 and October 2021 in three tertiary pediatric institutions evaluating the imaging findings in children and adolescents (≤ 18 years) with confirmed diagnoses of a PTEN mutation. For each patient, the imaging findings, histopathology reports, and at least a 2-year follow-up of clinical outcomes for non-operative cases were documented.

RESULTS

The cohort included 78 children (37 girls), with a mean age at diagnosis of 7.5 years (range 0 days to 18 years). Benign brain findings included enlarged Virchow-Robin perivascular spaces, white matter changes, developmental venous anomalies, and cerebellar hamartomas. Benign thyroid findings were common, but 5/45 (11.1%) with thyroid abnormalities had a malignant nodule. Soft tissue adipocytic tumors, GI/GU polyps, other soft tissue abnormalities, along with vascular anomalies in various anatomic locations were common.

CONCLUSION

Brain abnormalities, benign non-vascular soft tissue abnormalities, and vascular anomalies are commonly seen in children and adolescents with PTEN-related hamartoma tumor syndrome. However, malignancies involving the thyroid gland are not uncommon. Familiarity with the phenotype of PTEN-related hamartoma tumor syndrome in the pediatric population can improve diagnosis and prompt appropriate clinical surveillance of abnormal findings that warrant further management.

Beyond schwannomas and neurofibromas: a radiological and histopathological review of lesser-known benign lesions that arise in association with peripheral nerves

Peripheral nerve sheath tumors comprise a significant percentage of both benign and malignant soft tissue tumors. The vast majority of these lesions are schwannomas and neurofibromas, which most radiologists are familiar with including the well-described multimodality imaging features. However, numerous additional often under-recognized benign entities associated with nerves exist. These rarer entities are becoming increasingly encountered with the proliferation of cross-sectional imaging, particularly magnetic resonance imaging (MRI). It is important for the radiologist to have a basic understanding of these entities as many have near-pathognomonic MR imaging features as well as specific clinical presentations that when interpreted in concert, often allows for a limited differential or single best diagnosis. The ability to provide a prospective, pre-intervention diagnosis based solely on imaging and clinical presentation is crucial as several of these entities are "do not touch" lesions, for which even a biopsy may have deleterious consequences. To our knowledge, the majority of these benign entities associated with nerves have only been described in scattered case reports or small case series. Therefore, the aim of this article is to provide a radiopathologic comprehensive review of these benign entities that arise in association with nerves with a focus on characteristic MRI features, unique histopathologic findings, and entity specific clinical exam findings/presentation.

Mosaic RASopathy due to KRAS variant G12D with segmental overgrowth and associated peripheral vascular malformations

Oncogenic RAS variants lead to constitutive overactivation and increased signal transduction into downstream pathways. They are found as somatic driver events in various types of human cancer. In a somatic mosaic status, the same RAS variants have been associated with a wide spectrum of focal or segmental tissue dysplasia and overgrowth including various types of congenital nevi, vascular malformations, and other changes (mosaic RASopathies). We present a 3-year-old male patient with segmental overgrowth of the subcutaneous fatty tissue of the right lower extremity with colocalized arteriovenous and capillary malformations and dysplastic draining veins in combination with talipes equinovarus of the right foot. In tissue biopsies of the affected extremity, we identified a mosaic KRAS variant, c.35G>A (p.Gly12Asp), while this variant was absent in the DNA extracted from a biopsy of the normal extremity. This report provides further evidence for the wide clinical and phenotypic variability associated with mosaic KRAS variants. The described pattern confirms that the combination of segmental overgrowth and vascular anomalies in the form of arteriovenous and capillary malformations is a possible manifestation of a mosaic RASopathy. The accurate genetic diagnosis is crucial for molecular-targeted therapy, which might be a future therapeutic target for mosaic RASopathies.

[Diagnosis and management of vascular malformations : Interdisciplinary teamwork in demand]

Vascular anomalies are very rare, but can occur in children and adults in almost every region of the body. Due to the complexity of this disease, the path to a definitive diagnosis is often difficult. It requires interdisciplinary teamwork with close exchange of information between the individual treatment partners to reach the correct diagnosis and then to start the best therapy. This article provides an overview of the main types of vascular malformations from a clinical, imaging, and histological point of view, following the current classification of the International Society for the Study of Vascular Anomalies (ISSVA).

Plexiform fibrohistiocytic tumor: imaging features and clinical findings

OBJECTIVE

To describe the imaging features of plexiform fibrohistiocytic tumor and its associated clinical findings.

MATERIALS AND METHODS

An institutional database was searched to identify all patients with a pathological diagnosis of plexiform fibrohistiocytic tumor. The electronic medical record was reviewed for relevant clinical data. Radiologic images of the primary tumor site were reviewed by two radiologists to assess primary, residual, or recurrent tumor with respect to tumor location, size, morphology, MR signal characteristics and enhancement, and involvement of adjacent structures.

RESULTS

Thirteen patients with imaging of the primary tumor site were identified [eight female, five male; mean age, 15.9 years (range, 3-41 years)]. Plexiform fibrohistiocytic tumor typically manifested as a solitary, painless, firm, slow-growing lesion centered in the subcutaneous tissues, with a predilection for the upper extremity or head and neck region. Most tumors had a purely plaque-like or infiltrative morphology at MRI; some demonstrated no round or oval mass. Tumors were predominantly isointense to muscle on T1-weighted imaging and hyperintense on fluid-sensitive imaging, and enhanced after gadolinium contrast administration. Five patients (38%) had residual tumor after initial surgery, resembling postoperative changes. No patient had recurrent tumor. One patient (8%) developed metastases to local lymph nodes and to the lung. No patient died from plexiform fibrohistiocytic tumor.

CONCLUSIONS

Plexiform fibrohistiocytic tumor often manifests as a plaque-like or infiltrative process, sometimes without a round or oval mass, most commonly in the subcutaneous tissues of the upper extremity or head and neck region. Residual tumor is often present after initial surgery, and may be indistinguishable from postoperative changes.

Temporal Evolution and Management of Fast Flow Vascular Anomalies in PTEN Hamartoma Tumor Syndrome

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is characterized by formation of recurrent benign tumors described as PTEN hamartoma of soft tissue that may contain fast flow vascular anomalies (FFVA). The purpose of this study is to review the temporal evolution and management of FFVA in PHTS. A retrospective review of 22 patients (9 males), age 1 to 18 (median 9) years diagnosed with PHTS at a tertiary care pediatric hospital between October 2002 and August 2017 revealed 4 patients with FFVA. Imaging, management, and treatment complications were reviewed. During median follow-up of 8 (range: 4-13) years, ultrasound and magnetic resonance imaging performed for recurrent pain, showed progressive increase in the size of hamartomas and development of new FFVA in three-fourth patients. Medical management included pain medications, oral sirolimus, and physical and psychiatric therapy. Surgical excision of hamartoma ( n  = 1) resulted in recurrence within 3 months. Between 4 and 24 (average 1.5/year) embolizations were performed per patient. Pain related to FFVA responded well to embolization. Pain secondary to PTEN hamartoma responded poorly to percutaneous sclerosant injection, but demonstrated improvement with sirolimus. There was no correlation between serum sirolimus levels and frequency/timing of recurrence of FFVA/hamartoma. Complications included sclerosant migration into digital arteries ( n  = 1), subclavian vein stenosis due to glue migration ( n  = 1), oral mucositis ( n  = 4), and elevated triglycerides ( n  = 4). Patients with PHTS present with recurrent pain requiring life-long management with a multi-disciplinary team. Pain due to FFVA responds to embolization, and pain due to hamartoma responds to sirolimus. This improves quality of life, but does not prevent disease progression.