The salivary gland section in the 5th edition of the World Health Organization classification of head and neck tumors features a description and inclusion of several new entities, including sclerosing polycystic adenoma, keratocystoma, intercalated duct adenoma, and striated duct adenoma among the benign neoplasms; and microsecretory adenocarcinoma and sclerosing microcystic adenocarcinoma as the new malignant entities. The new entry also includes mucinous adenocarcinoma subdivided into papillary, colloid, signet ring, and mixed subtypes with recurrent AKT1 E17K mutation across patterns suggesting that mucin-producing salivary adenocarcinomas represent a histologically diverse single entity that may be related to salivary intraductal papillary mucinous neoplasm (IPMN). Cribriform adenocarcinoma of salivary gland origin (CASG) now represents a distinctive subtype of polymorphous adenocarcinoma (PAC). PAC is defined as a clinically, histologically and molecularly heterogeneous disease group. Whether CASG is a different diagnostic category or a subtype of PAC is still controversial. New defining genomic alterations have been characterized in many salivary gland tumors. In particular, they include gene fusions, which have shown to be tightly tumor-type specific, and thus valuable for use in diagnostically challenging cases. The recurrent molecular alterations were included in the definition of mucoepidermoid carcinoma, adenoid cystic carcinoma, secretory carcinoma, polymorphous adenocarcinoma, hyalinizing clear cell carcinoma, mucinous adenocarcinoma, and microsecretory adenocarcinoma. Importantly, the number of entities in the salivary chapter has been reduced by omitting tumors or lesions if they do not occur exclusively or predominantly in salivary glands, including hemangioma, lipoma, nodular fasciitis and hematolymphoid tumors. They are now discussed in detail elsewhere in the book.

Thymolipoma is an uncommon, non-malignant mediastinal mass characterized by a mixture of mature fat and normal thymic tissue. It typically grows slowly and is often asymptomatic until it reaches a large size, causing compressive symptoms. We report on a 19-year-old woman who sought medical attention for chest pain, dyspnoea, and anterior chest swelling. Imaging revealed a well-defined anterior mediastinal mass, and surgical excision was performed. Histopathological examination showed a well-encapsulated lesion with mature adipose tissue admixed with normal thymic parenchyma containing Hassall's corpuscles, confirming the diagnosis of thymolipoma. Complete surgical resection is both diagnostic and curative, with an excellent prognosis and negligible recurrence risk. Our findings underscore the importance of recognizing thymolipoma as a potential cause of anterior mediastinal masses, thereby preventing unnecessary radical treatment.

A 54-year-old female patient presented with a gradually enlarging mass on the ulnar side of the left wrist. Magnetic resonance imaging demonstrated a fat-containing lesion deep within the flexor carpi ulnaris that showed heterogeneous signal intensity, as well as weak internal and peripheral enhancement, which are not typical for atypical spindle cell/pleomorphic lipomatous tumors (ASPLTs). The imaging appearance overlapped with spindle cell lipoma (SCL), atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL), and hibernoma, which made preoperative diagnosis challenging. The mass was excised en bloc. Histologically, the tumor consisted of mature adipocytes with substantial size variation, mild atypical spindle cells within a myxoid stroma, and scattered lipoblasts. Immunohistochemistry showed CD34 positivity and loss of RB1, while MDM2 amplification was absent on fluorescence in situ hybridization analysis, supporting a diagnosis of ASPLT. ASPLT is known for its broad range of morphological and radiological presentations, and this case further highlights the difficulty inherent in distinguishing it from SCL and ALT/WDL based on imaging alone. Recognition of its diverse features and the use of molecular testing are essential for accurately diagnosing ASPLT. Surgical excision remains the standard treatment. Although recurrence has been reported, metastasis of ASPLT is exceedingly rare.

Lipoma arborescens is a rare intra-articular lesion typically associated with chronic monoarthritis. We report on a man in his 40s with psoriatic arthritis, well controlled with secukinumab, who developed chronic bilateral knee effusion and soft, non-tender suprapatellar masses over several years despite low systemic disease activity. Magnetic resonance (MR) imaging revealed frond-like fatty proliferation with effusion, which was confirmed as lipoma arborescens on histopathology. Bilateral synovectomy restored full knee extension and improved mobility and function. MR imaging is an excellent non-invasive tool to diagnose persistent knee swelling, guide management and prevent long-term complications.

Intradural lipomas are rare benign tumors, accounting for less than 1% of all spinal tumors. Their exact physiopathology is not fully understood. There are many theories that share some basic aspects. Cervical intradural lipomas not associated with dysraphism are even rarer. We report the case of an incidental finding of a nondysraphic cervical intradural lipoma in a 17-year-old male patient initially admitted for polytrauma management. Whole-body trauma CT revealed a well-circumscribed intradural extramedullary fat-density lesion within the left dorsolateral spinal canal at the C1-C2 level, demonstrating attenuation values consistent with fat and mild mass effect on the adjacent cervical cord without significant canal compromise. MRI confirmed a homogeneous lesion hyperintense on T1-weighted images, intermediate-to-hyperintense on T2-weighted images, with complete signal suppression on fat-saturated sequences and no enhancement or cord signal abnormality. As the patient was asymptomatic, a conservative management approach was implemented with annual MRI follow-up and clinical evaluation.

Background and aim Adipocytic tumors are among the most common soft tissue neoplasms, ranging from benign to malignant forms. Accurate differentiation between these entities is essential due to differences in prognosis and management. This study aims to evaluate the clinicopathological spectrum of lipomatous tumors, including their demographic profile, anatomical distribution, and histopathological spectrum, and to analyze factors associated with malignancy. Methods A retrospective observational study was conducted in the Department of Pathology at a tertiary care center from October 2019 to September 2025. A total of 114 histopathologically confirmed cases of adipocytic tumors were included. Clinical and pathological data were retrieved and analyzed. Tumors were classified according to the WHO classification. Ancillary techniques, including immunohistochemistry (MDM2 and CDK4), were performed in selected cases. Associations between tumor size, site, radiological features, and malignancy were assessed. Results The majority of patients were in the fourth to sixth decade age group (52 cases, 45%), with a male predominance (68 cases, 60%). The upper extremity was the most common site (32 cases, 28%), followed by the lower extremity (30 cases, 26%) and trunk (28 cases, 25%). Conventional lipoma was the most common tumor type (72 cases, 63%), followed by other variants such as fibrolipoma (12 cases, 11%) and angiolipoma (10 cases, 9%). The most common anatomical location was subcutaneous tissue, followed by deep soft tissue and intramuscular locations. Atypical lipomatous tumor/well-differentiated liposarcoma and myxoid liposarcoma were identified in a subset of cases. Radiologically, benign lesions showed homogeneous fat density, whereas malignant tumors demonstrated septal thickening, nodularity, and non-adipose components. Most tumors measured less than 5 cm (64 cases, 56%). MDM2/CDK4 immunohistochemistry findings indicate that atypical/malignant adipocytic neoplasms were positive in four cases. Conclusions Lipomatous tumors are predominantly benign, with lipoma being the most common subtype. Tumor size and location serve as important indicators of malignancy. Comprehensive histopathological evaluation, supplemented by ancillary techniques where necessary, is crucial for accurate diagnosis and appropriate management.

Swallowable intragastric balloon is a minimally invasive bariatric option for obesity, but severe intolerance requiring intervention is uncommon. We report a 41-year-old man with grade I obesity, hypertension, dyslipidemia, and hyperthyroidism who developed severe retrosternal pain, reflux, persistent vomiting, and oral intolerance 5 days after balloon placement. Computed tomography showed appropriate balloon position without migration or perforation but suggested a small hiatal hernia. Due to refractory symptoms, laparoscopic balloon removal was performed. Intraoperative findings revealed a larger hiatal hernia with paraesophageal lipoma than previously identified, prompting simultaneous hiatoplasty and conversion to Roux-en-Y gastric bypass. The patient had progressive postoperative recovery with symptom resolution and improved oral tolerance. This case highlights that severe balloon intolerance may reveal occult hiatal pathology despite inconclusive preoperative studies and demonstrates that single-stage laparoscopic balloon removal, hiatal hernia repair, and definitive bariatric surgery can be a safe, effective strategy in appropriately selected patients.

Adult colonic intussusception caused by lipoma is rarely seen in clinical practice. Due to its infrequency, it is often incidentally diagnosed radiologically in patients presenting with abdominal pain. The challenge of pre-operative diagnosis lies in distinguishing benign lead points such as lipomas from malignant tumours, given that colonic intussusception carries a high risk of underlying malignancy. Urgent diagnosis is therefore essential to exclude a malignant cause and guide appropriate surgical management. We describe a case of a transverse colo-colic intussusception in a 50-year-old female secondary to a histologically confirmed lipoma as the lead point. The patient underwent a right hemi-colectomy and recovered well post-operatively. This case emphasizes the importance of considering intussusception in adults with abdominal pain and highlights that, rarely, they may be caused by benign colonic lesions.