Postoperative Spindle Cell Nodule Pathology 

Updated: Jul 21, 2013
  • Author: Kenneth A Iczkowski, MD; Chief Editor: Liang Cheng, MD  more...
  • Print

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, Postoperative spindle cell nodule of the bladder, with muscularis propria on the left.
Next:

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.

Previous
Next:

Location

Postoperative spindle cell nodules are polypoid or nodular and involve any portion of the bladder wall, most commonly the dome.

Previous
Next:

Clinical Features and Imaging

Hematuria is the most common presenting symptom, present in most patients, followed by bladder outlet obstruction and dysuria.

Previous
Next:

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]

Previous
Next:

Microscopic Findings

Plasma cells are often less prominent than in inflammatory pseudotumors/inflammatory myofibroblastic tumors (IMTs).

Previous
Next:

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, 7]

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. [8]

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]

Previous