C57BL/6N mice are inbred strains widely used in biomedical research. Hence, a large amount of basic data has been accumulated. However, in the field of histopathology, spontaneous data for relatively younger mice that are used more frequently are not yet abundant, in contrast to data for older mice and their neoplastic lesions. To acquire the essential background data required by various research and toxicological assessments, 120 mice of the C57BL/6N strain (10 and 13 weeks of age) were collected from two institutions (From Korea and Japan) and subjected to histopathological analyses of the major organs (liver, spleen, kidney, thymus, heart, testis, epididymis). The results showed significantly higher incidence of sperm granulomas in the epididymides (10-56%) of these mice, compared with that in other strains or species of lab animals. Upon closer inspection, oligospermia/clear cell hyperplasia, cellular debris, and tubular vacuolation were also observed in the epididymides with sperm granulomas. Moreover, diseased organs were significantly heavier than healthy ones. Immunohistochemical staining showed a significant increase in the chromatic figures of cysteine-dependent aspartate-directed proteases-3 (caspase-3) and cleaved-poly(ADP-ribose) polymerase (c-PARP), and damages to the tubule due to spontaneous apoptosis, which may have led to the sperms leaking out of the tubule, causing the granuloma. To conclude, spontaneous sperm granuloma can occur in 10- and 13-week-old C57BL/6N mice and may thus affect the results of various studies using these mice. Therefore, sperm granuloma in epididymis needs to be carefully considered as an important factor when design the study using C57BL/6N.
Animals ; Apoptosis ; Epididymis* ; Granuloma* ; Heart ; Hyperplasia ; Incidence* ; Kidney ; Korea ; Male ; Mice* ; Spermatozoa* ; Spleen ; Testis ; Thymus Gland

Thymic hyperplasia is frequently observed in Graves' disease. However, detectable massive enlargement of the thymus is rare, and the mechanism of its formation has remained elusive. This case showed dynamic changes in thymic hyperplasia on serial computed tomography images consistent with changes in serum thyrotropin receptor (TSH-R) antibodies and thyroid hormone levels. Furthermore, the patient's thymic tissues underwent immunohistochemical staining for TSH-R, which demonstrated the presence of thymic TSH-R. The correlation between serum TSH-R antibody levels and thymic hyperplasia sizes and the presence of TSH-R in her thymus suggest that TSH-R antibodies could have a pathogenic role in thymic hyperplasia.
Adult ; Female ; Graves Disease/*complications/surgery/therapy ; Humans ; Male ; Receptors, Thyrotropin/blood ; Thymus Gland/diagnostic imaging ; Thymus Hyperplasia/*diagnostic imaging/etiology/immunology ; Thyroid Hormones ; Thyroidectomy ; Thyrotropin/blood ; Tomography, X-Ray Computed ; Young Adult

Ectopic mediastinal parathyroid adenomas or hyperplasias account for up to 25% of primary hyperparathyroidism cases. Most abnormal parathyroid glands are found in the superior mediastinum within the thymus and can be removed through a cervical incision; however, a few of these glands are not accessible using standard cervical surgical approaches. Surgical resection has traditionally been performed via median sternotomy or thoracotomy. However, recent advancement in video-assisted thoracic surgery techniques has decreased the need for sternotomy or thoracotomy to remove these ectopic parathyroid glands. Here, we report a successful case of video-assisted thoracoscopic removal of a mediastinal parathyroid adenoma.
Hyperparathyroidism, Primary ; Hyperplasia ; Mediastinum ; Parathyroid Glands ; Parathyroid Neoplasms* ; Sternotomy ; Thoracic Surgery, Video-Assisted ; Thoracotomy ; Thymus Gland

We present herein an unusual case of multilocular thymic cyst, with prominent lymphoid follicular hyperplasia, in a 64-year-old man. It was incidentally founded as a mediastinal mass on chest radiography, during a routine health check-up. Computed tomography revealed a cystic lesion, which contains thick septa involving the thymus. The resected mass, 8x4 cm in diameter, involved the thymus and there is no adhesion or invasion into the adjacent tissue. The cut surface showed cystic spaces with thick white-tan firm wall, which cysts contained gelatinous material. Microscopically, the lesion was characterized by multiple cysts, lined by flattened cuboidal epithelium that was separated by thick walls, having a dense lymphoid tissue with lymphoid follicles. The patient was discharged without any complication and is well without evidence of recurrence for sixteen months.
Epithelium ; Gelatin ; Humans ; Hyperplasia ; Lymphoid Tissue ; Mediastinal Cyst ; Mediastinal Diseases ; Middle Aged ; Recurrence ; Thorax ; Thymus Gland

OBJECTIVETo study the clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT).

METHODSThe clinical and pathologic findings were evaluated in 3 cases of biopsy confirmed thymic MALT lymphoma. The clincopathologic features, treatment and prognosis were discussed and literatures reviewed.

RESULTSOne male and two female patients presented with asymptomatic mediastinal masses with a history of Sjögren syndrome. They were aged 36, 35 and 41 years respectively, and only one patient had B symptoms. Grossly, all three tumors were encapsulated and had multiple variable-sized cysts on cut-surface. Histopathologically, the normal thymic lobular architecture was effaced by abnormal dense lymphoid infiltration. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding Hassall's corpuscles and epithelial cyst lining. All cases showed apparent plasmacytic differentiation. Immunohistochemically, the tumor cells were positive for CD20, CD79a, bcl-2 and negative for CD3, CD5, cyclin D1, CD43, CD10, bcl-6, and CD23. The plasma cells showed kappa light chain restriction. Immunoglobulin heavy chain rearrangement in three cases was confirmed by PCR. All patients were at early stage and received routine chemotherapy with or without radiotherapy after surgical removal. All patients achieved complete remission with 24, 18 and 3 months follow-up, respectively.

CONCLUSIONSPrimary thymic MALT lymphoma may be a rare distinctive lymphoma. It can be diagnosed by HE and immunohistochemical study and should be differentiated from reactive lymphoid proliferation, other types of lymphoma and mediastinal thymoma.

Adult ; Antibodies, Monoclonal, Murine-Derived ; therapeutic use ; Antigens, CD20 ; metabolism ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Cyclophosphamide ; therapeutic use ; Diagnosis, Differential ; Doxorubicin ; therapeutic use ; Female ; Follow-Up Studies ; Gene Rearrangement, B-Lymphocyte, Heavy Chain ; Humans ; Immunoglobulin Heavy Chains ; genetics ; Keratin-19 ; metabolism ; Lymphoma, B-Cell, Marginal Zone ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Male ; Prednisone ; therapeutic use ; Pseudolymphoma ; pathology ; Thymus Hyperplasia ; pathology ; Thymus Neoplasms ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Vincristine ; therapeutic use

We report a case of thymic hyperplasia accompanied by pericardial lipomatosis and right facial hemihypertrophy in an 8-year-old boy. On imaging studies, the hyperplastic thymus had prominent curvilinear and nodular fatty areas simulating a fat-containing anterior mediastinal mass, which is an unusual finding in children. To our knowledge, this is the first report on a child with a combination of thymic hyperplasia, pericardial lipomatosis, and right facial hemihypertrophy. The radiologic findings are presented with a brief discussion.
Child ; Diagnosis, Differential ; Facial Asymmetry/complications/*diagnosis ; Heart Diseases/complications/*diagnosis/surgery ; Humans ; Hypertrophy/pathology ; Lipomatosis/complications/*diagnosis/surgery ; Magnetic Resonance Imaging ; Male ; Pericardium/*pathology ; Thymus Hyperplasia/complications/*diagnosis/surgery ; Tomography, X-Ray Computed

Carcinoma showing thymus-like differentiation (CASTLE) is a very rare malignant neoplasm of the thyroid, which resembles lymphoepithelioma or squamous cell carcinoma of the thymus. It originates from ectopic thymic tissue or remnants of the branchial pouches. We recently experienced a case of CASTLE in the thyroid gland of a 65-year-old woman. The patient presented with a non-tender mass in the right thyroid gland and dyspnea and coughing upon bending. The patient was diagnosed with ‘cystic change of adenomatous goiter’ of the thyroid by fine needle aspiration cytology. Right thyroidectomy was performed because of nodular hyperplasia on frozen biopsy. Histologic examination of the resected tumor showed that the tumor was lobulated and expansive growth pattern, with fibrous septa dividing the tumor and infiltrated by lymphocytes and plasma cells. Tumor cells possessed oval, large vesicular nuclei and prominent nucleoli, and the immunohistochemical staining was positive for CD5. The patient was diagnosed with thyroid CASTLE. We performed complete thyroidectomy. There has been no local regional recurrence.
Aged ; Biopsy ; Biopsy, Fine-Needle ; Carcinoma, Squamous Cell ; Cough ; Dyspnea ; Female ; Humans ; Hyperplasia ; Lymphocytes ; Plasma Cells ; Recurrence ; Thymus Gland* ; Thyroid Gland ; Thyroidectomy

In the treatment of myasthenia gravis, thymectomy is generally accepted as the standard of therapy. For thymectomy, there have been various conventional open approaches including sternal splitting, but recently minimally invasive approaches have been increasingly applied. A 28-year-old man presenting with weakness of both hands and fatigability was diagnosed as having myasthenia gravis with thymic hyperplasia. He underwent a robot-assisted thymectomy with the 'da Vinci' surgical system. Through the right thoracic cavity, two thirds of the thymic gland was dissected, and the remainder was resected through the left; these procedures took, respectively, 1 hour and 30 minutes. The patient was discharged on the 8th postoperative day without complications. The minimally invasive approach with the 'da Vinci' surgical system is emerging as a popular choice and various advantages have been reported. Here we report the first successful case of robot-assisted thymectomy.
Adult ; Hand ; Humans ; Myasthenia Gravis ; Robotics ; Thoracic Cavity ; Thymectomy ; Thymus Hyperplasia

Spontaneous pneumomediastinum in a term newborn without mechanical ventilation or underlying lung disease is rare. We present a case of a newborn baby who developed respiratory distress after birth and cystic pneumomediastinum which improved spontaneously with thymic hyperplasia as demonstrated on chest radiography, CT and MRI. The combination of cystic pneumomediastinum and thymic hyperplasia in a newborn has not been reported, thus far.
Humans ; Hyperplasia ; Infant, Newborn ; Lung Diseases ; Mediastinal Emphysema ; Parturition ; Respiration, Artificial ; Thorax ; Thymus Gland ; Thymus Hyperplasia

True thymic hyperplasia and ectopic thymus are very rare in children. In embryologic aspect, thymus is distributed around cervical area and ends up in mediastinum. This case is simultaneous thymic hyperplasia of neck and mediastinum. Ectopic thymus in the neck and thymic hyperplasia in the mediastinum in children were reported 2 and 7 cases respectively in Korea. In Clinical aspects, these thymic hyperplasia were presented by mass. So we should suspect these benign condition to avoid unnecessary operation or biopsy. We report a case of true thymic hyperplasia in the mediastinum with ectopic thymus in the neck in a 4-month-old male infant and review the relevant literature. We believe this is the first reported case in the world of true thymus hyperplasia in the mediastinum with cervical ectopic thymus in the neck.
Biopsy ; Child ; Humans ; Infant ; Korea ; Male ; Mediastinum* ; Neck* ; Thymus Gland* ; Thymus Hyperplasia*