Malignant rhabdoid tumor is a clinically aggressive neoplasm that was initially described as a distinctive renal tumor of childhood. But among the malignant rhabdoid tumors, extrarenal rhabdoid tumor is rare. We report an extrarenal neoplasm histologically and ultrastructurally identical to renal rhabdoid tumor that arose in the retroperitoneum of a 4-month-old boy and presented as a right lower abdominal mass. The tumor had an aggressive clinical course despite multimodal therapeutic regimens, and the patient died with disseminated disease 12 months after diagnosis.
Diagnosis ; Humans ; Infant ; Male ; Rhabdoid Tumor*

Female ; Humans ; Kidney ; pathology ; Kidney Neoplasms ; diagnosis ; Rhabdoid Tumor ; diagnosis

We report a very rare case of sellar and suprasellar atypical teratoid rhabdoid tumor (ATRT) in a 42-year-old female patient. The tumor was removed subtotally with a transsphenoidal approach. Histopathologic study showed rhabdoid cells with prominent nucleoli and abundant cytoplasm. Immunohistochemistry for INI1 was completely negative in the tumor cells, consistent with ATRT. After surgery, she received radiotherapy including spinal irradiation with proton beam therapy and subsequent chemotherapy, with no evidence of recurrence for more than 2 years. Up to date, this is the 8th case of an adult-onset ATRT in the sellar or suprasellar region. Despite its rarity, ATRTs should be considered in the differential diagnosis of an unclear malignant sellar or suprasellar lesion in adult patients and the treatment strategies for adult ATRT patients could be differentiated from those of pediatric ATRT patients.
Adult ; Cytoplasm ; Diagnosis, Differential ; Drug Therapy ; Female ; Humans ; Immunohistochemistry ; Proton Therapy ; Radiotherapy ; Recurrence ; Rhabdoid Tumor*

Malignant Rhabdoid tumor is a rare malignant neoplasm and is morphologically similar to rhabdomyosarcoma, but is different immunohistochemically. Most malignant rhabdoid tumors occur in the kidney of infants, and are rarely reported at extrarenal sites. Since Frierson and his collagues first described the malignant extrarenal rhabdoid tumor(MRT) in children in 1985, it has rarely been reported. The neoplasm is histologically and immunohistochemically identical to a renal malignant rhabdoid tumor. There have been no previous reports of this neoplasm in Korea. An MRT of the sacroiliac bone in a 11-year-old girl is described. Five months after the initial presentation, the patient is still alive with partial response to combination chemotherapy and radiotherapy. The authors review previous reports of extrarenal MRT, and discuss the pathologic characteristics, differential diagnosis, and treatment of this rare neoplasm.
Child ; Diagnosis, Differential ; Drug Therapy, Combination ; Female ; Humans ; Infant ; Kidney ; Korea ; Radiotherapy ; Rhabdoid Tumor* ; Rhabdomyosarcoma

Objective: To investigate the clinicopathological characteristics and differential diagnosis of pediatric SMARCB1/INI1-deficient poorly differentiated chordoma (PDC) of the skull base. Methods: Five cases of SMARCB1/INI1-deficient PDC were identified in 139 cases of chordoma diagnosed in Sanbo Brain Institute, Capital Medical University, Beijing, China from March 2017 to March 2021. The clinical and imaging data of the 5 PDCs were collected. H&E and immunohistochemical staining, and DNA methylation array were used, and the relevant literatures were reviewed. Results: All 5 PDCs were located at the clivus. The average age of the patients was 6.4 years, ranging from 3 to 16 years. Three patients were female and two were male. Morphologically, in contrast with classical chordomas, they presented as epithelioid or spindle tumor cells organized in sheets or nests, with necrosis, active mitoses, and infiltration into surrounding tissue. All cases showed positivity of CKpan, EMA, vimentin and brachyury (nuclear stain), and loss of nuclear SMARCB1/INI1 expression. S-100 protein expression was not frequent (2/5). Ki-67 proliferative index was high (20%-50%). All cases had over-expressed p53. It was necessary to differentiate SMARCB1/INI1-dificient PDC from SMARCB1/INI1-dificient tumors occurring at skull base of children or the tumors with epithelial and spindle cell morphological features. The 3 PDCs with DNA methylation testing showed the methylation profiles different from the pediatric atypical teratoid/rhabdoid tumors. They formed an independent methylation profile cluster. The clinical prognosis of the 5 patients was poor, and the overall survival time was 2-17 months. Conclusions: PDC is a special subtype of chordoma, which often affects children and occurs in the clivus. The PDC shares epithelioid or spindle cell morphologic features which are different from the classic chordoma. Besides the typical immunohistochemical profile of chordoma, PDC also has loss of nuclear SMARCB1/INI1 expression and distinct epigenetic characteristics.
Biomarkers, Tumor/genetics* ; Child ; Chordoma/genetics* ; Diagnosis, Differential ; Female ; Humans ; Male ; Prognosis ; Rhabdoid Tumor/diagnosis* ; SMARCB1 Protein/genetics* ; Skull Base

Multicystic dysplastic kidney (MCDK) is a relatively common developmental anomaly in infants and children and has a good prognosis. In contrast, a malignant rhabdoid tumor of the kidney (MRTK) is one of the most lethal neoplasms of early life. However, the presentation of such a lethal tumor combined with multicystic dysplasia has not been reported to date. In this report, we describe a case of MRTK in a 5-yr-old girl who also had multicystic dysplasia. She was previously diagnosed with MCDK at birth due to a huge palpable mass on the right side of the abdomen. The right kidney was extensively replaced by numerous grossly dilated, variable-sized cysts. Microscopically, the tumor cells show a diffusely infiltrative growth pattern, which revealed large non-cohesive, round-to-polygonal tumor cells with vesicular nuclei. Some tumor cells had eccentric nuclei and large, round, eosinophilic cytoplasmic inclusions. There were metanephrons present, with the central ureteric bud and peripheral branches surrounded by condensing mesenchyma, immature glomeruli, and metaplastic cartilage in the adjacent parenchyma. To our knowledge, this is the first combined case of the two aforementioned diseases and this case may, in fact, suggest a new disease entity.
Child, Preschool ; Diagnosis, Differential ; Female ; Humans ; Kidney Neoplasms/*complications/*diagnosis ; Multicystic Dysplastic Kidney/*complications/*diagnosis ; Prognosis ; Rhabdoid Tumor/*complications/*diagnosis

Rhabdoid tumor of the kidney (RTK) is a rare malignancy in infancy. Central nervous system involvement in RTK is already known. However, solitary spinal metastasis in RTK has been hardly reported. The authors report a case of metastatic RTK to spine causing paraplegia in an 8-month-old girl. Since the patient was young, the diagnosis of spine metastasis was delayed until paraplegia was seen after radical nephrectomy. Thorough neurological examination should be performed for early diagnosis of spinal metastasis in young patients with RTK. If there are any abnormal signs in neurologic examination, magnetic resonance images of brain and spine are recommended.
Brain ; Central Nervous System ; Diagnosis ; Early Diagnosis ; Female ; Humans ; Infant* ; Kidney* ; Neoplasm Metastasis ; Nephrectomy ; Neurologic Examination ; Paraplegia ; Rhabdoid Tumor* ; Spine*

PURPOSE: To describe the CT and MR findings of primary malignant rhabdoid tumor (MRT) of the brain, which is a rare but very aggressive neoplasm in childhood. MATERIALS AND METHODS: Retrospectively, we evaluated the CT and MR findings of 5 patients of primary MRT of the brain with a review of clinical records. RESULTS: The primary MRTs of the brain were large (n = 4) with a tendency to be associated with necrosis, hemorrhage (n = 2) and calcification (n = 2). Solid components of the tumor showed increased attenuation on precontrast CT scan and iso- or slightly hyper-signal intensity on T2-weighted images probably due to hypercellularity. Solid components of the tumor were also well enhanced on contrast-enhanced CT scan (n = 5) and MRI (n = 2). In 1 case with intratumoral bleeding, MR findings were variable on T1-weighted and T2-weighted images. Intracranial and intraspinal metastasis were found in 2 cases on preoperative MR studies. Follow-up CT and MR studies showed recurrence of the tumor and/or leptomeningeal metastasis in 3 cases. CONCLUSIONS: Although CT and MR findings of primary MRT of the brain are nonspecific, a tendency toward large size, calcification and intratumoral bleeding may be attributed to CT and MR findings. The solid components of tumors could present hyperdense on precontrast CT scan and iso- or slightly hyper-signal intensity on T2-weighted MR image. Preoperative and follow-up MR studies are important to detect metastatic foci.
Adolescence ; Brain Neoplasms/pathology ; Brain Neoplasms/diagnosis* ; Child ; Child, Preschool ; Female ; Human ; Infant ; Magnetic Resonance Imaging* ; Male ; Retrospective Studies ; Rhabdoid Tumor/pathology ; Rhabdoid Tumor/diagnosis* ; Tomography, X-Ray Computed*

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.
Child* ; Diagnosis, Differential ; Female ; Hematoma ; Humans ; Kidney* ; Lymphatic Diseases ; Necrosis ; Retrospective Studies ; Rhabdoid Tumor* ; Tomography, X-Ray Computed

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.
Child* ; Diagnosis, Differential ; Female ; Hematoma ; Humans ; Kidney* ; Lymphatic Diseases ; Necrosis ; Retrospective Studies ; Rhabdoid Tumor* ; Tomography, X-Ray Computed