Gupta AK, Polavarapu H. Squamous cell carcinoma of unknown primary in the pelvis after complete remission following chemoradiotherapy: A case report. World J Clin Cases 2025; 13(33): 112160 [PMID: 41356084 DOI: 10.12998/wjcc.v13.i33.112160]
Corresponding Author of This Article
Anupam K Gupta, Department of General Surgery, SSM Health, 1 Good Samaritan Way, Mt Vernon, IL 62864, United States. dranupamkumargupta@gmail.com
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Multidisciplinary Sciences
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Case Report
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Nov 26, 2025 (publication date) through Jan 9, 2026
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World Journal of Clinical Cases
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Gupta AK, Polavarapu H. Squamous cell carcinoma of unknown primary in the pelvis after complete remission following chemoradiotherapy: A case report. World J Clin Cases 2025; 13(33): 112160 [PMID: 41356084 DOI: 10.12998/wjcc.v13.i33.112160]
World J Clin Cases. Nov 26, 2025; 13(33): 112160 Published online Nov 26, 2025. doi: 10.12998/wjcc.v13.i33.112160
Squamous cell carcinoma of unknown primary in the pelvis after complete remission following chemoradiotherapy: A case report
Anupam K Gupta, Harsha Polavarapu
Anupam K Gupta, Department of General Surgery, SSM Health, Mt Vernon, IL 62864, United States
Harsha Polavarapu, Department of Surgery, Blessing Hospital, Quincy, IL 62301, United States
Author contributions: Gupta AK and Polavarapu H designed the research study, drafted and revised the manuscript; Gupta AK collected the clinical data and performed the literature review; Polavarapu H was the managing physician and performed the procedure, assisted in pathological interpretation, and contributed to discussion writing. All authors read and approved the final manuscript.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Anupam K Gupta, Department of General Surgery, SSM Health, 1 Good Samaritan Way, Mt Vernon, IL 62864, United States. dranupamkumargupta@gmail.com
Received: July 21, 2025 Revised: August 16, 2025 Accepted: October 23, 2025 Published online: November 26, 2025 Processing time: 125 Days and 12.7 Hours
Abstract
BACKGROUND
Pelvic squamous cell carcinoma of unknown primary (CUP) is extremely rare, accounting for less than one percent of all CUP cases, and its infrequency has limited the development of standardized diagnostic and treatment guidelines.
CASE SUMMARY
A 77-year-old female with a history of resected lung adenocarcinoma presented with worsening constipation. Imaging revealed a 2.5 cm mass adjacent to the right levator ani muscle. Biopsy confirmed poorly differentiated squamous cell carcinoma, positive for pancytokeratin and p40, and negative for p16, cytokeratin 7, cytokeratin 20, and neuroendocrine markers. No primary lesion was identified despite extensive evaluation. She underwent five cycles of 5-fluorouracil (1000 mg/m2 continuous infusion, days 1-4) and mitomycin-C (10 mg/m2 on day 1) with concurrent pelvic radiotherapy (50.4 Gy in 28 fractions). Follow-up imaging demonstrated complete remission sustained for 12 months. Electrocorticography performance status improved from 2 at diagnosis to 1 during follow-up.
CONCLUSION
This case highlights the potential role of chemoradiotherapy in managing pelvic squamous cell CUP, achieving durable remission in selected patients.
Core Tip: This case report describes an elderly woman with pelvic squamous cell carcinoma of unknown primary (CUP), an entity accounting for less than 1% of CUP cases. A comprehensive diagnostic workup ruled out common primaries, and multidisciplinary evaluation led to chemoradiotherapy with 5-fluorouracil and mitomycin-C plus radiotherapy. The patient achieved complete remission for 12 months with improved functional status. This report emphasizes the value of imaging, pathology, and individualized multidisciplinary management in achieving durable remission in rare pelvic squamous CUP.
