Thoracic SMARCA4-Deficient Undifferentiated Tumor Presenting as a Giant Mediastinal Mass: A Case Report

30 July 2026 : Case report Japan

Challenging differential diagnosis, Rare disease, Educational Purpose (only if useful for a systematic review or synthesis)

Nanami Ichihashi^{ABCDEF 1}, Motona Kumagai

^{ABCDEF 2,3*}, Miyako Shimasaki^{BCDEF 2}, Akihiro Shioya

^{BCDEF 3,4}, Sohsuke Yamada

^{BCDEF 3,5}

DOI: 10.12659/AJCR.952937

Am J Case Rep 2026; 27:e952937

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Table 1 Clinical features, treatment strategies, and outcomes of SMARCA4-deficient tumors reported in the literature.

Study	Year	No. of cases	Age, years (median, range)	Sex (male/female)	Smoking history	Primary site	PD-L1 expression	Treatment	Outcome
Le Loarer et al []¹	2015	19	41 (28–72)	16/3	17/19 smokers	Mediastinum/pleura/lung	ND	Surgical resection; chemotherapy	Median OS: 7 months
Yoshida et al []²	2017	12	39 (27–82)	11/1	Predominantly smokers	Chest wall/thoracic cavity/mediastinum/lung	ND	Surgical resection; chemotherapy; radiotherapy	Median OS: 7 months
Perret et al []⁶	2019	30	48 (28–90)	27/3	Predominantly smokers	Mediastinum/pleura/lung	ND	Chemotherapy	Median OS: 6 months
Zhou et al []⁷	2024	20	61 (39–72)	20/0	Predominantly smokers	Lung/mediastinum/pleura/chest wall	ND	Various systemic therapies	Median OS: 5.6 months
Rekhtman et al []⁸	2020	22	58 (30–80)	16/6	Predominantly smokers	Lung/mediastinum/lymph node/bone	ND	ND	Median OS: 5.2 months
Ohta et al []¹²	2025	Systematic review (160)	58 (18–88)	112/48	Frequent	Thoracic (40%); digestive (17.5%); gynecologic (15.6%)	TPS ≥1%: 28/33; <1%: 4/33; ND: 1/33	Chemotherapy; immunotherapy; surgery	Median OS: 5.0 months
Shinno et al []¹³	2022	18	53 (32–80)	14/4	18/18 smokers	Thoracic	TPS ≥50%: 2/11; 1–49%: 5/11; < 1%: 4/11	Immune checkpoint inhibitors; chemotherapy	Median PFS: 2.4 months
Present case	–	1	67	1/0	Smoker	Anterior mediastinum	Negative	Radiotherapy + nivolumab/ipilimumab	OS: 6 months
Abbreviations: ND, not described/not available; OS, overall survival; PD-L1, programmed death-ligand 1; PFS, progression-free survival; TPS, tumor proportion score.

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