A case of desmoplastic myxoid tumor, SMARCB1 mutant, in the pineal region

Abstract

Desmoplastic myxoid tumor (DMT), SMARCB1 mutant is a recently proposed new entity that mainly occurs in the pineal region and has epigenetic features similar to those of atypical teratoid/rhabdoid tumors (AT/RT)‐MYC and poorly differentiated chordomas. Herein, we present a new case of a 33‐year‐old man with headaches, dizziness, nausea, vomiting, and blurred vision, who was initially found to have a suspicious germinoma on imaging. After surgical removal of the lesion, the postoperative pathological diagnosis was DMT, SMARCB1 mutant. To the best of our knowledge, this is the first case reported in China. Our findings also extend the range of the immunohistochemical phenotype of this rare tumor.

A case of an atypical teratoid/rhabdoid tumor with distinctive histology in the pineal region in an adult patient

“…Hence, AT/RT of the pineal region in adults, consisting of small short spindle‐shaped cells with abundant mucus matrix as in the present case, must be carefully distinguished from DMT, SMARCB1‐mutant. Clinically, DMT, SMARCB1‐mutant has a better prognosis than AT/RT, and no metastasis or dissemination has been reported to date 16–18 . However, in this case, cerebrospinal fluid dissemination occurred 4 months after the initial surgery, the disease progressed rapidly, and the patient died in 13 months.…”

“…Clinically, DMT, SMARCB1‐mutant has a better prognosis than AT/RT, and no metastasis or dissemination has been reported to date. 16 , 17 , 18 However, in this case, cerebrospinal fluid dissemination occurred 4 months after the initial surgery, the disease progressed rapidly, and the patient died in 13 months. Histologically, although there were similarities in the cell images of hematoxylin and eosin staining, the desmoplastic change was unclear and contained a small amount of rhabdoid cells.…”

“…Histologically, although there were similarities in the cell images of hematoxylin and eosin staining, the desmoplastic change was unclear and contained a small amount of rhabdoid cells. In addition, in the nine cases of DMT 16 , 17 , 18 reported to date, six out of eight cases were CD34‐positive, and in seven of the nine cases, Ki‐67 level was 5% or less. However, in the present case, CD34 was negative and Ki‐67 was as high as approximately 10%.…”

Newly Recognized CNS Tumors in the 2021 World Health Organization Classification: Imaging Overview with Histopathologic and Genetic Correlation

“…CD34 is positive, and INI1 is negative. [71][72][73] Unlike AT/RT, this tumor more commonly occurs in adults (median age, 40 years; range, 15-61 years). 15 Data are limited, but there does not appear to be a sex predilection.…”

“…72 On imaging, there is variable T1 signal, T2 intermediate signal, and enhancement. 71,73 Large tumors can compress the cerebral aqueduct and cause obstructive hydrocephalus. 71 Intracranial Mesenchymal Tumor, FET-CREB Fusion-Positive (Provisional Type) Intracranial mesenchymal tumor is a group of rare mesenchymal CNS tumors without an assigned WHO grade.…”