An adult with recurrent atypical teratoid rhabdoid tumor of the spine

Figures & data

Figure 1. Magnetic resonance imaging of the spine.

(A) Post-contrast T1-weighted sagittal image of initial tumor. (B) T1 Dixon sagittal image of recurrent tumor (12 years later) with extramedullary extradural soft tissue mass between C7 and T1. (C) Post-contrast T1-weighted axial image of initial tumor. (D) STIR sagittal image of recurrent tumor.

Table 1. Comprehensive overview of the patient's clinical course, detailing the initial diagnosis, treatment modalities employed at various stages and the response to therapies.

Date	Clinical event	Summary
8/2008	Initial presentation	The patient presented to the neurology clinic with a new onset of bilateral lower extremity weakness and numbness from the nipple level through his bilateral legs. Subsequent radiographic workup demonstrated a 44 × 32 × 29 mm lesion centered at the right Thoracic (T) spine level 3–4 neural foramen
8/23/2008	Surgery and initial diagnosis	Surgery: a CT-guided biopsy was performed, and during the biopsy, extreme bilateral lower extremity weakness and numbness developed, leading to subsequent emergency T3 laminectomy for tumor excision. The procedure also involved T1 through T5 pedicle screw fixation Pathology: the overall findings suggest a malignant ependymal neoplasm (anaplastic ependymoma) over a meningioma
9/11/2008–10/27/2008	Radiation and chemotherapy	T1–T4 radiation therapy was administered with a total dose of 6040 cGy, along with temodar (chemotherapy) at a dosage of 75 mg/m^2 during radiation
4/2018	Identification of recurrence on imaging	MRI images of the cervical and thoracic spine demonstrated an enlarging soft tissue mass within C7 and T1
5/3/2018	Biopsy	Biopsy of enlarging mass. Pathology findings: recurrent ependymoma
6/6/2018	Surgery	Surgery: C7-T1 tumor resection plus C5-T1 fusion. The tumor was sent for pathological evaluation Pathology: diagnosis of “malignant neoplasm, consistent with atypical teratoid/rhabdoid tumor, WHO grade IV, recurrent.” Genetic testing identified the presence of an SMARCB1 mutation
7/18/2018	Radiation	Stereotactic radiosurgery to area of recurrence
3/26/2019	Identification of recurrence on imaging	MRI demonstrates interval enlargement of enhancing lesion at T1
4/22/2019	Surgery	Cervical hardware revision and tumor removal
6/5/2019–7/15/2020	Antibody/immunotherapy	Pembrolizumab 200 mg IV every three weeks
7/1/2019–7/8/2019	Radiation	For the anterior T1 vertebral body lesion, a total of 2500 cGy was prescribed to the 100% isodose line (98% coverage), with 99% of the spinal cord at this level receiving a dose <11.4 Gy Note: the dose was delivered as five 500-cGy daily fractions on 1–3, 5, and 8 July 2019
7/10/2020	Surgery	C5-T5 hardware revision
8/5/2020	Antibody/immunotherapy	Start pembrolizumab 400 mg IV every six weeks
4/2021	Antibody/immunotherapy	Discontinue pembrolizumab 400 mg IV due to abnormal liver function tests
12/6/2023	Follow-up appointment	The patient is clinically and radiographically stable and will continue to have reevaluation in the clinic in six months for a new spine MRI and a follow-up appointment

Figure 2. The patient's atypical teratoid rhabdoid tumor (AT/RT) on histology.

H&E sections demonstrate a malignant neoplasm characterized by cells with vesicular chromatin and visible nucleoli in both the initial resection and the re-resection (A, C). Immunohistochemistry for BAF47 (INI1) shows loss of expression in tumor cells in both the initial resection (B) and the re-resection (D). Immunohistochemistry performed on the re-resection was positive for vimentin (E), smooth muscle actin (F), and EMA (G). PDL-1 (22C3) performed on the re-resection was positive in approximately 30% of neoplastic cells (H).

Table 2. Concise overview of the patient's differential diagnosis, covering considerations for both initial and recurrent tumors, immunohistochemistry findings and final diagnosis.

Differential diagnosis	Immunohistochemistry findings	Considerations for initial tumor or recurrent tumor	Final diagnosis
Metastatic carcinoma	Negative for cytokeratin	Initial	Ruled out
Hematopoietic neoplasm	Negative for CD45	Initial	Ruled out
Melanoma	Negative for MART-1, HMB-45	Initial	Ruled out
Anaplastic ependymoma	Positive for S-100, EMA, and GFAP	Initial, recurrent	Initial diagnosis
Atypical teratoid/rhabdoid tumor	Negative for GFAP, S-100 Positive for EMA, SMA, vimentin; loss of nuclear INI1 staining	Recurrent	Recurrent diagnosis