INTERESTING IMAGE
A Rare Case of Urachal Mucinous Adenocarcinoma Detected by 18F-FDG PET/CT Xin Li, MD, PhD, Songtao Liu, MD, PhD, Shuzhan Yao, MD, and Muwen Wang, MD, PhD Abstract: A 48-year-old woman presented with abdominal pain, and her initial investigations, which included an abdominal ultrasound and a pelvic MRI examination, revealed a dominant soft tissue mass abutting her left iliac bone, extensive pelvic adenopathy, and multiple osseous metastases. The findings were concerning for chondrosarcoma; however, biopsy results were consistent with mucinous carcinoma of unknown origin. A staging 18F-FDG PET/CT revealed a mildly FDG-avid soft tissue mass with scattered calcifications extending to the dome of the urinary bladder, highly suggestive of a primary tumor. Cystoscopy with tissue sampling of this mass demonstrated a primary mucinous adenocarcinoma of the urachus. Key Words: urachal mucinous adenocarcinoma, PET/CT, skeletal metastasis (Clin Nucl Med 2015;40: 282–285)
Received for publication July 25, 2014; revision accepted November 12, 2014. From the PET/CT Center, Shandong Provincial Hospital Affiliated to Shandong University, Shandong University, Jinan City, Shandong Province, China. Conflicts of interest and sources of funding: This work was funded in part by the research fund for excellent young scientists of Shandong Province (BS2012YY029). Reprints: Muwen Wang, MD, PhD, PET/CT Center, Shandong Provincial Hospital Affiliated to Shandong University, Shandong University, Jingwu Rd 324#, Jinan City, Shandong Province, 250021, China. E-mail: [email protected]. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/15/4003–0282
282
www.nuclearmed.com
REFERENCES 1. Agrawal AK, Bobiński P, Grzebieniak Z, et al. Pseudomyxoma peritonei originating from urachus—case report and review of the literature. Curr Oncol. 2014;21: e155–e165. 2. Loggie BW, Fleming RA, Hosseinian AA. Peritoneal carcinomatosis with urachal signet-cell adenocarcinoma. Urology. 1997;50:446–448. 3. Lamb BW, Vaidyanathan R, Laniado M, et al. Mucinous adenocarcinoma of the urachal remnant with pseudomyxoma peritonei. Urol J. 2010;7:138–139. 4. Martínez A, Ferron G, Mery E, et al. Peritoneal pseudomyxoma arising from the urachus. Surg Oncol. 2012;21:1–5. 5. Fanning DM, Sabah M, Conlon PJ, et al. An unusual case of cancer of the urachal remnant following repair of bladder exstrophy. Ir J Med Sci. 2011;180:913–915. 6. Paras FA Jr, Maclennan GT. Urachal adenocarcinoma. J Urol. 2008;180:720. 7. Ogaya Pinies G, Herranz Amo F, Escribano Patiño G, et al. Urachal adenocarcinoma. Case report and bibliographic review. Arch Esp Urol. 2012;65:498–501. 8. Guimarães MD, Bitencourt AG, Lima EN, et al. 18FDG PET/CT findings in the unusual urachal adenocarcinoma. Clin Nucl Med. 2014;39:831–834. 9. Morató-López AE, Corres-Castillo M, Isusi-Alcazar J, et al. Morphologicalmetabolic evaluation of the urachal mucinous adenocarcinoma by positron emission tomography-computed tomography (PET-CT) [in Spanish]. Rev Esp Med Nucl Imagen Mol. 2012;31:145–147. 10. Siefker-Radtke A. Urachal carcinoma: surgical and chemotherapeutic options. Expert Rev Anticancer Ther. 2006;6:1715–1721.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Urachal Adenocarcinoma by 18F-FDG PET/CT
FIGURE 1. Pelvic MRI scans of a 48-year-old woman with intermittent abdominal pain revealed extensive pelvic adenopathy with a dominant soft tissue mass abutting her left iliac bone as well as multiple destructive lesions in her pelvic bones and lumbar spine consistent with osseous metastases. A representative pelvic lymph node is pointed by an arrow in panel A (T2-weighted image [T2WI]). Her dominant left pelvic mass with increased signal intensity on fat-suppressed T1WI is displayed in panel B. An irregular mass abutting her urinary bladder is also shown in panels C (arrow, T1-weighted image) and D (T2WI); however, this finding was not highlighted in the initial MRI report. Percutaneous biopsy of the dominant pelvic mass and pelvic lymph nodes indicated mucinous carcinoma of unknown origin. Her gastroscopy and colonoscopy showed no relevant findings.
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.nuclearmed.com
283
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Li et al
FIGURE 2. The axial images (A–C) of the staging FDG PET/CT scan showed a soft tissue mass measuring 2.6 3.3 cm (arrow) with mild FDG uptake (SUVmax, 2.4) and scattered calcifications extending to the dome of the urinary bladder, highly suggestive of a primary tumor. FDG-avid nodal and osseous metastases were also noted, the dominant soft tissue mass adjacent to the left iliac bone demonstrating an SUVmax of 6.9 (D). Sagittal images revealed that the primary tumor was invading the space of Retzius (E, arrow). Cystoscopy with tissue sampling of this mass was consistent with primary mucinous adenocarcinoma of the urachus. Given the extensive nodal and osseous metastases, the patient was graded with stage IV disease. The MIP view is displayed in panel F.
284
www.nuclearmed.com
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Urachal Adenocarcinoma by 18F-FDG PET/CT
FIGURE 3. Histology results of the primary tumor consistent with urachal mucinous adenocarcinoma. Hematoxylin-eosin staining (200) shows pools of extracellular mucin containing malignant epithelium as irregular glands (A). Immunohistochemical analysis reveals tumor cells with positive staining for CDX-2 (B), CK19 (C), and CK20 (D). The urachus is a tubular structure extending medially from the apex of the bladder to the allantoid during fetal development and is normally obliterated after birth. Its lumen is lined with a transitional epithelium that has the potential for focal glandular metaplasia and malignant transformation.1 Primary urachal adenocarcinoma is a rare tumor, accounting for only 0.01% of all malignancies2,3 and for 0.17% to 0.34% of all bladder tumors.3–5 The clinicopathological diagnostic criteria include tumor growth in the dome of urinary bladder wall extending to the space of Retzius, a sharp demarcation between tumor and surface epithelium, and exclusion of a primary adenocarcinoma in another location with secondary bladder involvement.6 Urachal tumors can be divided into 5 histological subtypes: intestinal, mucinous, signet ring, unspecified, and mixed types.7 18F-FDG PET/CT has been reported useful not only for evaluating the disease extent,8,9 but also for searching the primary tumor in patients with advanced metastatic disease. Urachal tumors tend to be associated with a poor prognosis, with 5-year survival rates ranging from 9.0% to 43%.7 Surgical resection with en bloc excision of the urachus is the treatment of choice.10
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.nuclearmed.com
285
A Rare Case of Urachal Mucinous Adenocarcinoma Detected by 18F-FDG PET/CT Xin Li, MD, PhD, Songtao Liu, MD, PhD, Shuzhan Yao, MD, and Muwen Wang, MD, PhD Abstract: A 48-year-old woman presented with abdominal pain, and her initial investigations, which included an abdominal ultrasound and a pelvic MRI examination, revealed a dominant soft tissue mass abutting her left iliac bone, extensive pelvic adenopathy, and multiple osseous metastases. The findings were concerning for chondrosarcoma; however, biopsy results were consistent with mucinous carcinoma of unknown origin. A staging 18F-FDG PET/CT revealed a mildly FDG-avid soft tissue mass with scattered calcifications extending to the dome of the urinary bladder, highly suggestive of a primary tumor. Cystoscopy with tissue sampling of this mass demonstrated a primary mucinous adenocarcinoma of the urachus. Key Words: urachal mucinous adenocarcinoma, PET/CT, skeletal metastasis (Clin Nucl Med 2015;40: 282–285)
Received for publication July 25, 2014; revision accepted November 12, 2014. From the PET/CT Center, Shandong Provincial Hospital Affiliated to Shandong University, Shandong University, Jinan City, Shandong Province, China. Conflicts of interest and sources of funding: This work was funded in part by the research fund for excellent young scientists of Shandong Province (BS2012YY029). Reprints: Muwen Wang, MD, PhD, PET/CT Center, Shandong Provincial Hospital Affiliated to Shandong University, Shandong University, Jingwu Rd 324#, Jinan City, Shandong Province, 250021, China. E-mail: [email protected]. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/15/4003–0282
282
www.nuclearmed.com
REFERENCES 1. Agrawal AK, Bobiński P, Grzebieniak Z, et al. Pseudomyxoma peritonei originating from urachus—case report and review of the literature. Curr Oncol. 2014;21: e155–e165. 2. Loggie BW, Fleming RA, Hosseinian AA. Peritoneal carcinomatosis with urachal signet-cell adenocarcinoma. Urology. 1997;50:446–448. 3. Lamb BW, Vaidyanathan R, Laniado M, et al. Mucinous adenocarcinoma of the urachal remnant with pseudomyxoma peritonei. Urol J. 2010;7:138–139. 4. Martínez A, Ferron G, Mery E, et al. Peritoneal pseudomyxoma arising from the urachus. Surg Oncol. 2012;21:1–5. 5. Fanning DM, Sabah M, Conlon PJ, et al. An unusual case of cancer of the urachal remnant following repair of bladder exstrophy. Ir J Med Sci. 2011;180:913–915. 6. Paras FA Jr, Maclennan GT. Urachal adenocarcinoma. J Urol. 2008;180:720. 7. Ogaya Pinies G, Herranz Amo F, Escribano Patiño G, et al. Urachal adenocarcinoma. Case report and bibliographic review. Arch Esp Urol. 2012;65:498–501. 8. Guimarães MD, Bitencourt AG, Lima EN, et al. 18FDG PET/CT findings in the unusual urachal adenocarcinoma. Clin Nucl Med. 2014;39:831–834. 9. Morató-López AE, Corres-Castillo M, Isusi-Alcazar J, et al. Morphologicalmetabolic evaluation of the urachal mucinous adenocarcinoma by positron emission tomography-computed tomography (PET-CT) [in Spanish]. Rev Esp Med Nucl Imagen Mol. 2012;31:145–147. 10. Siefker-Radtke A. Urachal carcinoma: surgical and chemotherapeutic options. Expert Rev Anticancer Ther. 2006;6:1715–1721.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Urachal Adenocarcinoma by 18F-FDG PET/CT
FIGURE 1. Pelvic MRI scans of a 48-year-old woman with intermittent abdominal pain revealed extensive pelvic adenopathy with a dominant soft tissue mass abutting her left iliac bone as well as multiple destructive lesions in her pelvic bones and lumbar spine consistent with osseous metastases. A representative pelvic lymph node is pointed by an arrow in panel A (T2-weighted image [T2WI]). Her dominant left pelvic mass with increased signal intensity on fat-suppressed T1WI is displayed in panel B. An irregular mass abutting her urinary bladder is also shown in panels C (arrow, T1-weighted image) and D (T2WI); however, this finding was not highlighted in the initial MRI report. Percutaneous biopsy of the dominant pelvic mass and pelvic lymph nodes indicated mucinous carcinoma of unknown origin. Her gastroscopy and colonoscopy showed no relevant findings.
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.nuclearmed.com
283
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Li et al
FIGURE 2. The axial images (A–C) of the staging FDG PET/CT scan showed a soft tissue mass measuring 2.6 3.3 cm (arrow) with mild FDG uptake (SUVmax, 2.4) and scattered calcifications extending to the dome of the urinary bladder, highly suggestive of a primary tumor. FDG-avid nodal and osseous metastases were also noted, the dominant soft tissue mass adjacent to the left iliac bone demonstrating an SUVmax of 6.9 (D). Sagittal images revealed that the primary tumor was invading the space of Retzius (E, arrow). Cystoscopy with tissue sampling of this mass was consistent with primary mucinous adenocarcinoma of the urachus. Given the extensive nodal and osseous metastases, the patient was graded with stage IV disease. The MIP view is displayed in panel F.
284
www.nuclearmed.com
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Clinical Nuclear Medicine • Volume 40, Number 3, March 2015
Urachal Adenocarcinoma by 18F-FDG PET/CT
FIGURE 3. Histology results of the primary tumor consistent with urachal mucinous adenocarcinoma. Hematoxylin-eosin staining (200) shows pools of extracellular mucin containing malignant epithelium as irregular glands (A). Immunohistochemical analysis reveals tumor cells with positive staining for CDX-2 (B), CK19 (C), and CK20 (D). The urachus is a tubular structure extending medially from the apex of the bladder to the allantoid during fetal development and is normally obliterated after birth. Its lumen is lined with a transitional epithelium that has the potential for focal glandular metaplasia and malignant transformation.1 Primary urachal adenocarcinoma is a rare tumor, accounting for only 0.01% of all malignancies2,3 and for 0.17% to 0.34% of all bladder tumors.3–5 The clinicopathological diagnostic criteria include tumor growth in the dome of urinary bladder wall extending to the space of Retzius, a sharp demarcation between tumor and surface epithelium, and exclusion of a primary adenocarcinoma in another location with secondary bladder involvement.6 Urachal tumors can be divided into 5 histological subtypes: intestinal, mucinous, signet ring, unspecified, and mixed types.7 18F-FDG PET/CT has been reported useful not only for evaluating the disease extent,8,9 but also for searching the primary tumor in patients with advanced metastatic disease. Urachal tumors tend to be associated with a poor prognosis, with 5-year survival rates ranging from 9.0% to 43%.7 Surgical resection with en bloc excision of the urachus is the treatment of choice.10
© 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.nuclearmed.com
285
