Schwann cells are found in the peripheral nervous system and can sometimes appear as benign hamartoma lesions in various parts of the body. Although rare in the gastrointestinal (GI) tract, they have been observed in the colon. Recently, mucosal Schwann cell hamartomas of the GI tract have been studied, and it was discovered that they had yet to be investigated up to 2009. In this context, we present the case of a 60-year-old man who was found to have lesions in the transverse colon during a routine colonoscopy. No further investigations were conducted since these lesions have not been associated with any risk of malignancy transformation and have not been linked to any inherited syndromes.
CONCLUSIONS: Mucosal Schwann cell hamartomas are rare types of polyps that can be found anywhere in the gastrointestinal tract.They are benign lesions not usually associated with any inherited syndrome and they are usually found incidentally by endoscopy.These polyps are benign and might not require further follow-up once diagnosed.

This study investigated the efficacy of single-phase dual-energy CT (DECT) in differentiating pulmonary hamartomas from malignant lung lesions using virtual non-contrast (VNC), iodine, and fat quantification. Forty-six patients with 47 pulmonary lesions (mean age: 65.2 ± 12.1 years; hamartomas-to-malignant lesions = 22:25; male: 67%) underwent portal venous DECT using histology, PET-CT and follow-up CTs as a reference. Quantitative parameters such as VNC, fat fraction, iodine density and CT mixed values were statistically analyzed. Significant differences were found in fat fractions (hamartomas: 48.9%; malignancies: 22.9%; p ≤ 0.0001) and VNC HU values (hamartomas: -20.5 HU; malignancies: 17.8 HU; p ≤ 0.0001), with hamartomas having higher fat content and lower VNC HU values than malignancies. CT mixed values also differed significantly (p ≤ 0.0001), but iodine density showed no significant differences. ROC analysis favored the fat fraction (AUC = 96.4%; sensitivity: 100%) over the VNC, CT mixed value and iodine density for differentiation. The study concludes that the DECT-based fat fraction is superior to the single-energy CT in differentiating between incidental pulmonary hamartomas and malignant lesions, while post-contrast iodine density is ineffective for differentiation.

Folliculosebaceous cystic hamartoma (FSCH) is a rare and benign form of cutaneous hamartomas. These skin lesions often lead to clinical and histopathological misdiagnosis due to their similarities to cutaneous lesions with overproduction of clustered sebaceous glands. Clinically, the lesions often present as solitary, skin-colored, pedunculated warts to cauliflower-like, exophytic papules and nodules, usually with a diameter ranging 0.5-1.5 cm that rarely exceed 2 cm in size. Only a small number of giant variants are reported in the literature with a diameter in the range of 5-23 cm. The vast majority of the lesions appear in the central face and show a striking predilection for the nose, ears, and scalp, but also emerge on the nipples, extremities, and genitals. Histologically, the epithelial components of folliculosebaceous cystic hamartoma comprise dilated infundibular cystic proliferation with surrounding mesenchymal components, which commonly include fibroplasia and vascular and adipose tissue proliferation. These histological characteristics were coined by Kimura and colleagues (1991). To the best of our knowledge, our case represents the biggest variant of giant folliculosebaceous cystic hamartoma.

BACKGROUND: Von Meyenburg complexes are benign hamartomatous lesions, they are part of the spectrum of ductal plate malformations. They are rare, reported in 0.35-5.6% of the general population, predominantly in adults, with no clear predilection for sex.
OBJECTIVE: To present the clinical characteristics of Von Meyenburg complexes in our region.
METHODS: We searched all cases with diagnosis of Von Meyenburg complexes in a period from 2012 to 2022, in our institutions.
RESULTS: We identified eight cases, with an average age of 59.25 years, with a predominance of females and with one case associated with gastric carcinoma.
CONCLUSIONS: It is important to adequately recognize this entity, since due to its multifocal nature it can easily simulate metastasis, additionally, and its presence does not rule out other synchronous neoplasms.
BACKGROUND: Los complejos de Von Meyenburg son lesiones hamartomatosas benignas que forman parte del espectro de las malformaciones de la placa ductal. Son poco frecuentes, se reportan en un 0.35-5.6% de la población general, predominantemente en adultos, sin clara predilección por un sexo.
OBJECTIVE: Presentar las características clínicas de los complejos de Von Meyenburg en nuestro medio.
UNASSIGNED: Se buscaron todos los casos con diagnóstico de complejos de Von Meyenburg en nuestras instituciones entre 2012 y 2022.
RESULTS: Identificamos ocho casos, con un promedio de edad de 59.25 años, con predominio por el sexo femenino y con un caso asociado a carcinoma gástrico.
CONCLUSIONS: Es importante reconocer y diagnosticar adecuadamente esta afección, ya que por su naturaleza multifocal fácilmente puede simular metástasis, y además su presencia no descarta otros procesos neoplásicos sincrónicos.

Cowden syndrome (CS) is a rare disease that was first described in 1963 and later included in the large group of genodermatoses. It is the most common syndrome among the PTEN-associated hamartomatous tumor syndromes (PHTS). CS has an autosomal dominant inheritance pattern, with increased penetrance and variable expressivity, making early diagnosis difficult. Mutations in the PTEN gene (phosphatase and TENsin homolog) are involved in its pathogenesis, involving many organs and systems originating in the three embryonic layers (ectodermum, endodermum, and mesodermum). The consequence is the development of hamartomatous lesions in various organs (brain, intestines, thyroid, oropharyngeal cavity, colon, rectum, etc.). Multiple intestinal polyps are common in patients with CS, being identified in over 95% of patients undergoing colonoscopy. The authors describe the case of a patient who presented the first signs of the disease at 3 ½ years (tonsil polyp) but was diagnosed only at the age of 20 following a colonoscopy that revealed hundreds of intestinal polyps, suggesting further molecular testing. A heterozygous frameshift mutation was identified in the PTEN gene, classified as a potentially pathogenic variant (c.762del.p(Val255*)). The authors present this case to highlight the path taken by the patient from the first symptoms to the diagnosis and to emphasize the clinical aspects of this mutational variant that have still not been identified in other patients with this syndrome.

OBJECTIVE: Stiff skin syndrome (SSS) is a rare disorder characterized by \"rock hard\" indurated skin affecting different body parts. The localized variant poses a diagnostic challenge, as it is frequently mistaken for other inflammatory connective tissue disorders. The aim of this study is to provide insightful clinical, radiologic and diagnostic data that might prove useful for the evaluation, management and treatment of pediatric patients with segmental SS.
METHODS: This single-center cohort study included patients ≤18 years diagnosed with localized SSS from 1988 to 2021 in a quaternary pediatric healthcare center in Toronto, Canada. Data included demographics, clinical, histopathologic and radiologic features, treatments, and clinical course. Data were summarized with descriptive statistics (mean, standard deviation, medians, interquartile ranges [IQRs]) and frequencies.
RESULTS: A total of 11 patients were included. The sclerotic changes were measured clinically and radiologically, by a total of 16 imaging studies: 13 magnetic resonance imaging (MRI) and 3 ultrasound. MRI readings showed abnormal high signal intensity of the affected tissue correlating with the anatomical site of involvement in all cases, specifically, in the shoulder/pelvic girdle with limb extension. Shear wave ultrasound elastography (SWE) demonstrated higher values within the dermis compared to the control site.
CONCLUSIONS: The presence of segmental sclerotic changes that affects the pelvic/shoulder girdle with extension to the extremities, in the absence of inflammation on biopsy and abnormal signaling intensity on imaging is suggestive of SSS. Skin SWE is a feasible, noninvasive, and objective instrument to evaluate and monitor sclerotic changes overtime, it could be potentially extrapolated to other pediatric skin sclerotic conditions.

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare, aggressive tumor mainly found in children but can also appear in adults. Its diagnosis in adults remains a conundrum; it is often identified late due to its non-specific symptoms and resemblance to benign lesions. A comprehensive treatment regimen involving surgical intervention, chemotherapy, and possibly radiation significantly boosts survival rates. Imaging often yields inconclusive outcomes, further complicating the diagnostic process. Here, we report the case of a 28-year-old female diagnosed with UESL, emphasizing the need for timely intervention. Undifferentiated embryonal sarcoma of the liver requires differentiation from a variety of hepatic tumors in adults. Though there are no distinctive characteristics to differentiate UESL from other hepatic masses, its morphology and immunohistochemical profiles significantly vary. The staging often reveals UESL as a large, well-defined mass with the potential for diverse differentiation. Its prognosis has been considerably improved with the advent of multidisciplinary treatment. Surgical resection remains a cornerstone, often combined with chemotherapy. While pediatric cases exhibit better overall survival rates than adults, outcomes heavily depend on the chosen treatment regimen. A combination of chemotherapy and complete tumor removal has been found to significantly elevate survival chances. Disease recurrence remains a challenge and is influenced by treatment strategy. In conclusion, the diagnosis and treatment of UESL are fraught with challenges, particularly in adults. A multidimensional approach, combining various therapies, is paramount for better outcomes. Continuous research and enhanced awareness are crucial for improving diagnostic precision and treatment outcomes for UESL patients.

OBJECTIVE: Lung carcinoids and atypical hamartomas may be difficult to differentiate but require different treatment. The aim was to differentiate these tumors using contrast-enhanced CT semantic and radiomics criteria.
METHODS: Between November 2009 and June 2020, consecutives patient operated for hamartomas or carcinoids with contrast-enhanced chest-CT were retrospectively reviewed. Semantic criteria were recorded and radiomics features were extracted from 3D segmentations using Pyradiomics. Reproducible and non-redundant radiomics features were used to training a random forest algorithm with cross-validation. A validation-set from another institution was used to evaluate of the radiomics signature, the 3D \'median\' attenuation feature (3D-median) alone and the mean value from 2D-ROIs.
RESULTS: Seventy-three patients (median 58 years [43‒70]) were analyzed (16 hamartomas; 57 carcinoids). The radiomics signature predicted hamartomas vs carcinoids on the external dataset (22 hamartomas; 32 carcinoids) with an AUC = 0.76. The 3D-median was the most important in the model. Density thresholds < 10 HU to predict hamartoma and > 60 HU to predict carcinoids were chosen for their high specificity > 0.90. On the external dataset, sensitivity and specificity of the 3D-median and 2D-ROIs were, respectively, 0.23, 1.00 and 0.13, 1.00 < 10 HU; 0.63, 0.95 and 0.69, 0.91 > 60 HU. The 3D-median was more reproducible than 2D-ROIs (ICC = 0.97 95% CI [0.95‒0.99]; bias: 3 ± 7 HU limits of agreement (LoA) [- 10‒16] vs. ICC = 0.90 95% CI [0.85‒0.94]; bias: - 0.7 ± 21 HU LoA [- 4‒40], respectively).
CONCLUSIONS: A radiomics signature can distinguish hamartomas from carcinoids with an AUC = 0.76. Median density < 10 HU and > 60 HU on 3D or 2D-ROIs may be useful in clinical practice to diagnose these tumors with confidence, but 3D is more reproducible.
UNASSIGNED: Radiomic features help to identify the most discriminating imaging signs using random forest. \'Median\' attenuation value (Hounsfield units), extracted from 3D-segmentations on contrast-enhanced chest-CTs, could distinguish carcinoids from atypical hamartomas (AUC = 0.85), was reproducible (ICC = 0.97), and generalized to an external dataset.
CONCLUSIONS: • 3D-\'Median\' was the best feature to differentiate carcinoids from atypical hamartomas (AUC = 0.85). • 3D-\'Median\' feature is reproducible (ICC = 0.97) and was generalized to an external dataset. • Radiomics signature from 3D-segmentations differentiated carcinoids from atypical hamartomas with an AUC = 0.76. • 2D-ROI value reached similar performance to 3D-\'median\' but was less reproducible (ICC = 0.90).

Folliculosebaceous cystic hamartoma is a cutaneous malformation composed of a cystic folliculosebaceous structure associated with mesenchymal elements, generally consisting of fibrous stroma, adipocytes and small vascular channels. We report the case of a 55-year-old female patient with a cutaneous nodule of the right nasal wing. Microscopically, the lesion showed a dilated hair follicle with multiple sebaceous glands, surrounded by a mesenchymal component composed of fibromyxoid stroma, spindle cells, mature-appearing adipocytes and collagen bundles, resembling spindle cell lipoma, associated with an additional neural component, consisting of small nerve bundles. In folliculosebaceous cystic hamartoma, the association of spindle cell lipomatous and neural components has not previously reported.

A 17-year-old male presented for review of a widespread keratinocytic epidermal nevus (KEN) in the setting of a chronic pericardial effusion. Biopsy of the epidermal nevus revealed a KRAS mutation. Pericardiocentesis revealed a chylous effusion and magnetic resonance lymphangiogram demonstrated an underlying lymphatic malformation. There are rare case reports of KEN with an associated KRAS mutation. This case highlights the importance of being alert to epidermal nevus syndrome, particularly in patients with a widespread nevus and seemingly unrelated pathology.