Postoperative Spindle Cell Nodule Pathology
- Author: Kenneth A Iczkowski, MD; Chief Editor: Liang Cheng, MD more...
Definition
Postoperative spindle cell nodules (PSCNs) are usually described as histologically identical to inflammatory myofibroblastic tumors (IMTs), except that a history of instrumentation or trauma to the bladder can be elicited (see the image below).[1, 2, 3, 4]
Postoperative spindle cell nodule of the bladder, with muscularis propria on the left. Epidemiology
The male-to-female ratio ranges from 2:1[1] to 3:1.[2, 3] The first large series of 38 cases comprised patients aged 2.5 months to 87 years.[3] The mean patient age was 65 years.
Location
Postoperative spindle cell nodules are polypoid or nodular and involve any portion of the bladder wall, most commonly the dome.
Clinical Features and Imaging
Hematuria is the most common presenting symptom, present in most patients, followed by bladder outlet obstruction and dysuria.
Gross Findings
Tumor size ranges from 1-10 cm (with 4 cm being the mean).[2] The mean tumor size is comparable with that of inflammatory pseudotumor/inflammatory myofibroblastic tumor (IMT), as well as sarcoma.[3]
Microscopic Findings
Plasma cells are often less prominent than in inflammatory pseudotumors/inflammatory myofibroblastic tumors (IMTs).
Immunohistochemistry
Immunoreactivity is identical to that of inflammatory pseudotumor/inflammatory myofibroblastic tumor (IMT). Some cases have been reported positive for ALK-1.[2, 5, 6]
In a study by Sukov et al, detection of ALK protein and ALK gene rearrangements were found to be useful in distinguishing inflammatory myofibroblastic tumor from spindle cell malignancies in the urinary bladder. The authors additionally noted that ALK rearrangement is the primary mechanism for ALK activation and that IMT likely represents a heterogeneous group of spindle cell proliferations, with the majority associated with ALK translocations.[7]
In separate studies, Tsuzuki et al and Freeman et al also confirmed results supporting that ALK-1 immunostaining is useful in differentiating IMT from other malignant spindle cell neoplasms of the bladder.[5, 6]
Montgomery EA, Shuster DD, Burkart AL, et al. Inflammatory myofibroblastic tumors of the urinary tract: a clinicopathologic study of 46 cases, including a malignant example inflammatory fibrosarcoma and a subset associated with high-grade urothelial carcinoma. Am J Surg Pathol. Dec 2006;30(12):1502-12. [Medline].
Harik LR, Merino C, Coindre JM, Amin MB, Pedeutour F, Weiss SW. Pseudosarcomatous myofibroblastic proliferations of the bladder: a clinicopathologic study of 42 cases. Am J Surg Pathol. Jul 2006;30(7):787-94. [Medline].
Iczkowski KA, Shanks JH, Gadaleanu V, et al. Inflammatory pseudotumor and sarcoma of urinary bladder: differential diagnosis and outcome in thirty-eight spindle cell neoplasms. Mod Pathol. Oct 2001;14(10):1043-51. [Medline].
Njim L, Dhouibi A, Binous Y, Touil N, Zakhama A, Moussa A. [Pseudosarcomatous myofibroblastic proliferation of the bladder]. Prog Urol. Apr 2010;20(4):307-10. [Medline].
Tsuzuki T, Magi-Galluzzi C, Epstein JI. ALK-1 expression in inflammatory myofibroblastic tumor of the urinary bladder. Am J Surg Pathol. Dec 2004;28(12):1609-14. [Medline].
Freeman A, Geddes N, Munson P, Joseph J, Ramani P, Sandison A, et al. Anaplastic lymphoma kinase (ALK 1) staining and molecular analysis in inflammatory myofibroblastic tumours of the bladder: a preliminary clinicopathological study of nine cases and review of the literature. Mod Pathol. Jul 2004;17(7):765-71. [Medline].
Sukov WR, Cheville JC, Carlson AW, Shearer BM, Piatigorsky EJ, Grogg KL, et al. Utility of ALK-1 protein expression and ALK rearrangements in distinguishing inflammatory myofibroblastic tumor from malignant spindle cell lesions of the urinary bladder. Mod Pathol. May 2007;20(5):592-603. [Medline].
Young RH. Tumor-like lesions of the urinary bladder. Mod Pathol. Jun 2009;22 Suppl 2:S37-52. [Medline].
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