INVERTED PAPILLOMA OF BLADDER
LAWRENCE
G. HEFTER,
IRA S. YOUNG,
M.D.
M.D.
From the Department of Pathology, and Section of Urology, Fairfax Hospital, Falls Church, Virginia, and Department of Urology, George Washington University Medical Center, Washington, D.C.
ABSTRACT - Thefifth reported case of a rare variant of transitional papillary tumor of the bladder termed inverted papilloma is reported with a brief review of the literature. This tumor is likely to be confused with invasive malignant papillary carcinoma although it has a distinct histologic pattern, and it is fm this reason that attention is drawn to the entity.
Since the first report of inverted urothelial papilloma in 1963 only 3 additional cases have been reported. ‘B2We now rep0 rt a fifth case. Case Report A sixty-five-year-old white man experienced a single episode of painless hematuria. The patient had also noted progressive and intermittent symptoms of lower urinary obstruction. Otherwise he was in general good health. Blood pressure was 142/70 mm. Hg. The prostate was 1 plus enlarged and benign to palpation. Routine complete blood cell count and urinalysis were normal. Intravenous pyelogram demonstrated normal upper urinary tracts. There was increased postvoiding residual. Panendoscopic examination showed no evidence of urethral or prostatic lesions. A contracture of the bladder neck was present. Cystoscopic examination revealed a 2.5cm. pedunculated lesion arising just inside the right portion of the bladder neck. The mass protruded into the bladder neck in a ball-valve fashion. The tumor had a slightly irregular, glistening, pink-tan surface. The over-all appearance, however, was smoother than the usual papillary lesion, and scattered yellow flecks were present on the tumor surface. The lesion obscured the right ureteral orifice. The remainder of the bladder was normal. Transurethral resection was done; cystoscopic examination ten months postoperatively showed no recurrence.
688
Pathologic findings The specimen consisted of four portions of gray-tan formalin-fixed tissue ranging from 0.4 to 1.5 cm. in greatest dimension and having an aggregate mass 1.8 cm. in diameter. Histologically the tumor consisted of ramifying cords and columns of cells invaginating into the underlying stroma from the surface epithelium (Fig. 1A). Both the surface epithelium and the inverted portions were lined with well-differentiated transitional epithelium showing slight focal crowding but without significant atypicality or mitotic figures (Fig. 1B). Gland-like spaces were focally present often being filled with eosinophilic material which was positive for mucin with colloidal iron and mucicarmine stains (Fig. 1C). The cells lining these zones ranged from flattened to columnar and did not contain mucin except at the free cytoplasmic border. In some areas squamoid differentiation was apparent but intercellular bridges or keratin was not seen. The stroma was loose and areolar with moderately prominent and sometimes dilated congested blood vessels. Comment Tumors of the bladder, renal pelvis, and ureter tend to be papillary and exophytic without invasion of the underlying stroma or muscle until grade 2 or 3 is reached with evidence of cellular atypicality, partial loss of polarity, and mitoses.
UROLOGY
/ MAY 1975 / VOLUME
V, NUMBER 5
FIGURE 1. (A) Low-power photomicrograph of portion of tumor showing smooth outer surface with invagination of epithelial cords into underlying stroma. (B) High-power photomicrograph showing welldifferentiated transitional epithelium comprising ramifying cords within loose stroma; and (C) glandular spaces having columnar inner lining cells; special stains demonstrate mucin at borders of these cells and within the lumen.
FIGURE 2. (A) Another portion of tumor containing gland-like spaces. (B) Inverted papilloma of nose showing histologic similarity to inverted papilloma of bladder (A).
The inverted papilloma, on the other hand, has a pattern of invagination but without significant cytologic atypicality (Fig. 2A). In this respect it has a strong microscopic resemblance to the inverted papilloma of the nose or nasal sinuses (Fig. 2B). The urothelial inverted papilloma occurs in the region of the bladder neck, trigone, and prostatic urethra. They are typically pedunculated and covered with flat rather than papilusually have cyst-like lomatous epithelium, spaces which may contain mucin, and have some tendency toward squamous metaplasia. It is well known that urothelial epithelium has the potential to undergo metaplastic change into intestinal type epithelium as is seen in the progression from Brunn’s nests to cystitis cystica and cystitis glandularis.3*4 Inflammation is thought to be the stimulus for this metaplastic change. Inverted papillomas have not been associated with inflammation and are regarded as true neoplasms. The stimulus for the inverted pattern thus far is unknown as is the relation it bears to the usual papillary carcinoma of the urinary system.
UROLOGY
/ MAY1975
I VOLUMEV,
NUMBER5
689
The danger with these tumors is overdiagnosis as they can easily be mistaken for malignant invasive tumors. Although thus far none have been shown to recur after local excision, they should be regarded as potentially malignant. The patients should be carefully followed because they may have a low-grade malignant potential as is the case with inverted papilloma of the nose.5’6 The Fairfax Hospital Falls Church, Virginia 22046 (DR. HEFTER)
References and HIRST, E.: Inverted papilloma of the bladder, J. Urol. 90: 175 (1963).
1. POTTS, I. F.,
2. TRITE& A. E. W.: Inverted urothelial papilloma: report of two cases, ibid. 101: 212 (1969). 3. GORDON,A.: Intestinal metaplasia of the urinary tract epithelium, J, Pathol. Bacterial. 85: 441 (1963). 4. PATCH, F. S., and RHEA, L. J.: The genesis and development of Brunn’s nests and their relationship to cystitis cystica, glandularis and primary adeno-carcinoma of the bladder, Can. Med. Assoc. J. 33: 597 (1935). Personal communication, 1974. 5. TRITES, A. E. W.: Personal communication, 1974. 6. PO-I-B, I. F.:
UROLOGY
I
MAY 1975 / VOLUME V, NUMBER 5
LAWRENCE
G. HEFTER,
IRA S. YOUNG,
M.D.
M.D.
From the Department of Pathology, and Section of Urology, Fairfax Hospital, Falls Church, Virginia, and Department of Urology, George Washington University Medical Center, Washington, D.C.
ABSTRACT - Thefifth reported case of a rare variant of transitional papillary tumor of the bladder termed inverted papilloma is reported with a brief review of the literature. This tumor is likely to be confused with invasive malignant papillary carcinoma although it has a distinct histologic pattern, and it is fm this reason that attention is drawn to the entity.
Since the first report of inverted urothelial papilloma in 1963 only 3 additional cases have been reported. ‘B2We now rep0 rt a fifth case. Case Report A sixty-five-year-old white man experienced a single episode of painless hematuria. The patient had also noted progressive and intermittent symptoms of lower urinary obstruction. Otherwise he was in general good health. Blood pressure was 142/70 mm. Hg. The prostate was 1 plus enlarged and benign to palpation. Routine complete blood cell count and urinalysis were normal. Intravenous pyelogram demonstrated normal upper urinary tracts. There was increased postvoiding residual. Panendoscopic examination showed no evidence of urethral or prostatic lesions. A contracture of the bladder neck was present. Cystoscopic examination revealed a 2.5cm. pedunculated lesion arising just inside the right portion of the bladder neck. The mass protruded into the bladder neck in a ball-valve fashion. The tumor had a slightly irregular, glistening, pink-tan surface. The over-all appearance, however, was smoother than the usual papillary lesion, and scattered yellow flecks were present on the tumor surface. The lesion obscured the right ureteral orifice. The remainder of the bladder was normal. Transurethral resection was done; cystoscopic examination ten months postoperatively showed no recurrence.
688
Pathologic findings The specimen consisted of four portions of gray-tan formalin-fixed tissue ranging from 0.4 to 1.5 cm. in greatest dimension and having an aggregate mass 1.8 cm. in diameter. Histologically the tumor consisted of ramifying cords and columns of cells invaginating into the underlying stroma from the surface epithelium (Fig. 1A). Both the surface epithelium and the inverted portions were lined with well-differentiated transitional epithelium showing slight focal crowding but without significant atypicality or mitotic figures (Fig. 1B). Gland-like spaces were focally present often being filled with eosinophilic material which was positive for mucin with colloidal iron and mucicarmine stains (Fig. 1C). The cells lining these zones ranged from flattened to columnar and did not contain mucin except at the free cytoplasmic border. In some areas squamoid differentiation was apparent but intercellular bridges or keratin was not seen. The stroma was loose and areolar with moderately prominent and sometimes dilated congested blood vessels. Comment Tumors of the bladder, renal pelvis, and ureter tend to be papillary and exophytic without invasion of the underlying stroma or muscle until grade 2 or 3 is reached with evidence of cellular atypicality, partial loss of polarity, and mitoses.
UROLOGY
/ MAY 1975 / VOLUME
V, NUMBER 5
FIGURE 1. (A) Low-power photomicrograph of portion of tumor showing smooth outer surface with invagination of epithelial cords into underlying stroma. (B) High-power photomicrograph showing welldifferentiated transitional epithelium comprising ramifying cords within loose stroma; and (C) glandular spaces having columnar inner lining cells; special stains demonstrate mucin at borders of these cells and within the lumen.
FIGURE 2. (A) Another portion of tumor containing gland-like spaces. (B) Inverted papilloma of nose showing histologic similarity to inverted papilloma of bladder (A).
The inverted papilloma, on the other hand, has a pattern of invagination but without significant cytologic atypicality (Fig. 2A). In this respect it has a strong microscopic resemblance to the inverted papilloma of the nose or nasal sinuses (Fig. 2B). The urothelial inverted papilloma occurs in the region of the bladder neck, trigone, and prostatic urethra. They are typically pedunculated and covered with flat rather than papilusually have cyst-like lomatous epithelium, spaces which may contain mucin, and have some tendency toward squamous metaplasia. It is well known that urothelial epithelium has the potential to undergo metaplastic change into intestinal type epithelium as is seen in the progression from Brunn’s nests to cystitis cystica and cystitis glandularis.3*4 Inflammation is thought to be the stimulus for this metaplastic change. Inverted papillomas have not been associated with inflammation and are regarded as true neoplasms. The stimulus for the inverted pattern thus far is unknown as is the relation it bears to the usual papillary carcinoma of the urinary system.
UROLOGY
/ MAY1975
I VOLUMEV,
NUMBER5
689
The danger with these tumors is overdiagnosis as they can easily be mistaken for malignant invasive tumors. Although thus far none have been shown to recur after local excision, they should be regarded as potentially malignant. The patients should be carefully followed because they may have a low-grade malignant potential as is the case with inverted papilloma of the nose.5’6 The Fairfax Hospital Falls Church, Virginia 22046 (DR. HEFTER)
References and HIRST, E.: Inverted papilloma of the bladder, J. Urol. 90: 175 (1963).
1. POTTS, I. F.,
2. TRITE& A. E. W.: Inverted urothelial papilloma: report of two cases, ibid. 101: 212 (1969). 3. GORDON,A.: Intestinal metaplasia of the urinary tract epithelium, J, Pathol. Bacterial. 85: 441 (1963). 4. PATCH, F. S., and RHEA, L. J.: The genesis and development of Brunn’s nests and their relationship to cystitis cystica, glandularis and primary adeno-carcinoma of the bladder, Can. Med. Assoc. J. 33: 597 (1935). Personal communication, 1974. 5. TRITES, A. E. W.: Personal communication, 1974. 6. PO-I-B, I. F.:
UROLOGY
I
MAY 1975 / VOLUME V, NUMBER 5
