Osteoid osteoma accounts for approximately 10% of all benign bone tumors, but only approximately 4% of cases occur in the foot and ankle area. Periarticular osteoid osteoma frequently manifests with nonspecific clinical symptoms that mimic other conditions, potentially leading clinicians down a diagnostic side path and resulting in delayed or missed diagnoses compared to extra-articular osteoid osteoma. Although plain radiographs may show nonspecific findings, magnetic resonance imaging can detect bone marrow edema and surrounding soft tissue changes. Computed tomography is the most accurate modality for diagnosis. This paper reports the case of a 26-year-old female diagnosed with periarticular osteoid osteoma of the calcaneus and was treated with arthroscopic localized curettage at the author’s institution.

Purpose: Neoadjuvant treatment (NAT) is now the standard for borderline resectable pancreatic cancer (RPC) and is being considered for RPC. Early recurrence after curative surgery in RPC is often seen as a treatment failure, prompting considerations for NAT. Our goal was to develop an artificial intelligence (AI)-based predictive model utilizing preoperatively available factors to forecast early recurrences of resected RPC. Methods: This study included 469 patients who underwent surgery for RPC between 2011 and 2019. Clinicopathologic and oncologic data were retrospectively reviewed. Preoperative variables, including laboratory data and imaging findings, were collected. Early recurrence was defined as recurrence occurring within a year after surgery. Deep neural networks were then used to select variables by assessing their importance. A new model predicting early recurrence of RPC was subsequently developed. Results: Of the patients evaluated, 199 (42.4%) experienced early recurrence. The predictive model included 14 preoperative variables: CA 19-9, preoperative pancreatitis, serum albumin, platelet count, lymphocyte count, the American Society of Anesthesiologists physical status classification, tumor size, monocyte count, age, body mass index, CRP, hemoglobin, WBC count, and CEA. The area under the curve for the model was 0.786 in the training set and 0.734 in the test set. Conclusion We developed an AI-based model to predict the early recurrence of RPC using preoperative parameters. By identifying patients at risk of early recurrence, optimal individualized treatments such as NAT can be considered. Future prospective studies are crucial to establish clear indications for NAT in RPC.

A seventeen-year-old Shih Tzu presented with severe abdominal distension and labored respiration. Radiographic examination revealed severe ascites and pleural effusion. Bilateral malignant ovarian tumor, which was non-resectable due to distant metastasis, was diagnosed through computed tomography and cytology. Chemotherapy with carboplatin significantly delayed fluid accumulation, improving quality of life for 6 months. Necropsy later confirmed metastatic malignant bilateral granulosa cell tumor involving lymph nodes, liver, and thoracic cavity. This case demonstrates the feasibility of chemotherapy and symptomatic management as alternatives to ovariohysterectomy in metastatic ovarian tumors, highlighting its potential to extend survival and maintain quality of life when surgery is contraindicated.

These guidelines aim to establish the standard practice for diagnosing and treating patients with differentiated thyroid cancer (DTC). Based on the Korean Thyroid Association (KTA) Guidelines on DTC management, the “Treatment of Advanced DTC” section was revised in 2024 and has been provided through this chapter. Especially, this chapter covers surgical and nonsurgical treatments for the local (previous surgery site) or regional (cervical lymph node metastasis) recurrences. After drafting the guidelines, it was finalized by collecting opinions from KTA members and related societies. Surgical resection is the preferred treatment for local or regional recurrence of advanced DTC. If surgical resection is not possible, nonsurgical resection treatment under ultrasonography guidance may be considered as an alternative treatment for local or regional recurrence of DTC. Furthermore, if residual lesions are suspected even after surgical resection or respiratory-digestive organ invasion, additional radioactive iodine and external radiation treatments are considered.

Pediatric differentiated thyroid cancers (DTCs), mostly papillary thyroid cancer (PTC, 80-90%), are diagnosed at more advanced stages with larger tumor sizes and higher rates of locoregional and/or lung metastasis. Despite the higher recurrence rates of pediatric cancers than of adult thyroid cancers, pediatric patients demonstrate a lower mortality rate and more favorable prognosis. Considering the more advanced stage at diagnosis in pediatric patients, preoperative evaluation is crucial to determine the extent of surgery required. Furthermore, if hereditary tumor syndrome is suspected, genetic testing is required. Recommendations for pediatric DTCs focus on the surgical principles, radioiodine therapy according to the postoperative risk level, treatment and follow-up of recurrent or persistent diseases, and treatment of patients with radioiodine-refractory PTCs on the basis of genetic drivers that are unique to pediatric patients.

Differentiated thyroid cancer demonstrates a wide range of clinical presentations, from very indolent cases to those with an aggressive prognosis. Therefore, diagnosing and treating each cancer appropriately based on its risk status is important. The Korean Thyroid Association (KTA) has provided and amended the clinical guidelines for thyroid cancer management since 2007. The main changes in this revised 2024 guideline include 1) individualization of surgical extent according to pathological tests and clinical findings, 2) application of active surveillance in low-risk papillary thyroid microcarcinoma, 3) indications for minimally invasive surgery, 4) adoption of World Health Organization pathological diagnostic criteria and definition of terminology in Korean, 5) update on literature evidence of recurrence risk for initial risk stratification, 6) addition of the role of molecular testing, 7) addition of definition of initial risk stratification and targeting thyroid stimulating hormone (TSH) concentrations according to ongoing risk stratification (ORS), 8) addition of treatment of perioperative hypoparathyroidism, 9) update on systemic chemotherapy, and 10) addition of treatment for pediatric patients with thyroid cancer.

The primary objective of initial treatment for thyroid cancer is minimizing treatment-related side effects and unnecessary interventions while improving patients’ overall and disease-specific survival rates, reducing the risk of disease persistence or recurrence, and conducting accurate staging and recurrence risk analysis. Appropriate surgical treatment is the most important requirement for this purpose, and additional treatments including radioactive iodine therapy and thyroid-stimulating hormone suppression therapy are performed depending on the patients’ staging and recurrence risk. Diagnostic surgery may be considered when repeated pathologic tests yield nondiagnostic results (Bethesda category 1) or atypia of unknown significance (Bethesda category 3), depending on clinical risk factors, nodule size, ultrasound findings, and patient preference. If a follicular neoplasm (Bethesda category 4) is diagnosed pathologically, surgery is the preferred option. For suspicious papillary carcinoma (suspicious for malignancy, Bethesda category 5), surgery is considered similar to a diagnosis of malignancy (Bethesda category 6). As for the extent of surgery, if the cancer is ≤1 cm in size and clinically free of extrathyroidal extension (ETE) (cT1a), without evidence of cervical lymph node (LN) metastasis (cN0), and without obvious reason to resect the contralateral lobe, a lobectomy can be performed. If the cancer is 1-2 cm in size, clinically free of ETE (cT1b), and without evidence of cervical LN metastasis (cN0), lobectomy is the preferred option. For patients with clinically evident ETE to major organs (cT4) or with cervical LN metastasis (cN1) or distant metastasis (M1), regardless of the cancer size, total thyroidectomy and complete cancer removal should be performed at the time of initial surgery. Active surveillance may be considered for adult patients diagnosed with low-risk thyroid papillary microcarcinoma. Endoscopic and robotic thyroidectomy may be performed for low-risk differentiated thyroid cancer when indicated, based on patient preference.