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Year : 2017  |  Volume : 60  |  Issue : 3  |  Page : 409-411
Nonspecific granulomatous prostatitis in association with eosinophilic epithelial metaplasia and prostatic adenocarcinoma

1 Department of Pathology, Jossigny Hospital, Jossigny, France
2 Department of General and Clinical Pathology, Medical University - Plovdiv, Plovdiv, Bulgaria

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Date of Web Publication22-Sep-2017


We present the first case of nonspecific granulomatous prostatitis (NSGP) associated with both eosinophilic epithelial metaplasia (EM) in benign glands and prostatic adenocarcinoma (PCa). The patient was a 68-year old man with a history of obstructive prostatic syndrome. After a transurethral resection of the prostate, the histologic analysis revealed NSGP and PCa. EM was seen in benign peri-granulomatous secretory epithelial cells as PAS Diastase positive granular eosinophilic transformation of the apical cell cytoplasm. This unusual cell appearance closely simulated the Paneth cell-like changes found in PCa. Negative chromogranin expression and weakly positive P504S immune staining in the foci of EM, surrounded by P63 positive basal cells confirmed the benign EM - phenotype. The combination of NSGP with both EM and PCa has not been reported in medical literature so far. Some observations concerning their differential diagnosis are suggested.

Keywords: Eosinophilic metaplasia, nonspecific granulomatous prostatitis, Paneth cell-like changes, prostatic adenocarcinoma

How to cite this article:
Dikov DI, Koleva MS, Peshev ZK, Belovezhdov VT. Nonspecific granulomatous prostatitis in association with eosinophilic epithelial metaplasia and prostatic adenocarcinoma. Indian J Pathol Microbiol 2017;60:409-11

How to cite this URL:
Dikov DI, Koleva MS, Peshev ZK, Belovezhdov VT. Nonspecific granulomatous prostatitis in association with eosinophilic epithelial metaplasia and prostatic adenocarcinoma. Indian J Pathol Microbiol [serial online] 2017 [cited 2023 Apr 1];60:409-11. Available from:

   Introduction Top

Nonspecific granulomatous prostatitis (NSGP) is a relatively uncommon type of chronic self-limited inflammation of the prostate, frequently mistaken with prostatic adenocarcinoma (PCa) on digital investigation, trans-rectal ultrasound, serum prostate specific antigen (PSA) test, and histopathological examination.

The coexistence of NSGP and PCa has been rarely reported.[1],[2]

Eosinophilic epithelial metaplasia (EM) is characterized with the presence of large, intensely eosinophilic cytoplasmic granules in benign prostatic epithelium.[3] The association of NSGP and EM has been described in a single case report.[4] The simultaneous combination of NSGP with both EM and PCa has not been reported so far.

   Case Report Top

A 68-year-old male was presented with perineal pain, disorders in the micturition, dysuria, and pollakiuria. A markedly enlarged and indurated prostate was detected upon digital rectal examination. Serum PSA level was within the normal range (3.8 ng/mL). No history of asthma, allergy, systemic granulomatous disease, previous prostate surgery, or radiation therapy was reported. Transurethral resection of the prostate (TURP) was performed and 35 g of prostatic tissue was available for analysis. Small foci (2-3 mm in diameter) were observed, some of which resembled cysts whilst others appeared as slightly elevated soft yellowish-green granules in a lobular pattern.

On microscopic examination, NSGP showed a lobulocentric proliferation of epithelioid histiocytes (hematoxylin-phloxine-saffron stained sections) [Figure 1]. Multinucleated giant cells, eosinophils, neutrophils, and lymphocytes were detected in the lesion. The stainings for acid-fast bacilli and Fungi were negative in non-caseating granulomas.
Figure 1: Nonspecific granulomatous prostatitis in the left side and eosinophilic metaplasia in benign prostatic epithelium in the right side of the image (hematoxylin-phloxine-saffron, ×100)

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In two TURP - fragments, the diagnosis of PCa was made - Gleason's score 6 (3 + 3) (pT1a, TNM 2009). No areas with neuroendocrine differentiation with Paneth cell-like changes (PCLCs)[5] were found in PCa after chromogranin - staining (data not shown).

Besides the malignant process in the prostate, approximately half of the benign secretory epithelial cells of adjacent NSGP ducts and acini showed EM [Figure 1]: strongly eosinophilic apical cytoplasm, filled with numerous bright small round granules [Figure 2]. The granules were PAS diastase positive [Figure 3], chromogranin negative, and had weakly positive focal apical staining for P504S, in the presence of strongly positive signal for p63 in the basal cells of the same acini [Figure 4]. In PCa, the expression of the last two markers was just the opposite: P504S showed intensive and diffuse staining of tumor cells while basal cells were negative (data not shown).
Figure 2: Eosinophilic metaplasia shows characteristic eosinophilic granules with apical location in the cell cytoplasm (hematoxylin-phloxine-saffron, ×400)

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Figure 3: Eosinophilic metaplasia in the prostate: The cells contain periodate Schiff's procedure and diastase-resistant cytoplasmic granules (periodic acid-Schiff with diastase, ×400)

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Figure 4: Eosinophilic metaplasia in the prostate: The cells shows weakly apical false-positive P504S immune staining and they are surrounded by P63 positive basal cells (combined P504S/P63 immunostain, ×400)

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   Discussion Top

The basic interest in the present case is the coexistence of NSGP and both EM in benign prostatic glands and PCa.

Granulomatous prostatitis (GP) is a characteristic histopathologic reaction to a variety of prostatic insults with nonspecific dense lobular inflammatory infiltrates containing histiocytes, lymphoplasmocytes, leukocytes, and scattered giant cells.[6] NSGP is defined as histologically granulomatous inflammation of the prostate with no specific causative agent, BCG treatment, surgery, systemic granulomatous disease, and fungal infection.[6] NSGP is the most frequent type of GP observed at histological examination in 77.7% of the cases.[6],[7] The frequency of NSGP is very low and varies from 0.36% to 3.4% of all histologically investigated materials of the prostate gland: prostate needle biopsies, radical prostatectomies, TURP, and adenomectomies.[1],[6],[7] It is usually self-limiting and results from excretory duct obstruction with extravasation of secretions and a subsequent autoimmune inflammatory reaction.[6],[7]

Clinically, GP may mimic PCa in 59% of cases when it is presented as a diffuse or nodular enlargement with firm to hard consistency.[8] PSA levels may be normal or increased.[1],[7] Histologically, 4% of NSGP cases mimic high Gleason grade PCa.[7] In such cases, an immunohistochemical panel including antibodies to CD68, PSA, and cytokeratins is recommended.[8]

However, NSGP may rarely coexist with PCa. There are only five cases documented up to now.[1],[2] We describe the sixth similar association. Although being infrequently found, all cases of NSGP should be thoroughly sampled and studied to exclude the presence of carcinomatous foci.[2]

The present concept of eosinophilic cytoplasmic changes in prostatic epithelium involves two different processes: EM in benign prostate epithelium and PCLC in PCa - epithelium with neuro-endocrine differentiation.[3] PCLC of the prostatic epithelium is considered to be a distinct form of neuroendocrine differentiation.[5] The condition is more common than previously reported and it is not associated with tumor grade, serum PSA levels, or pathologic stage.[5]

The frequency of EM varies from 12% to 23% of prostatic needle biopsies and presents 20% of the total prostatectomies.[3] Only single cases of EM in TURP - material have been described.[9]

The coexistence of NSGP and EM is very uncommon and it is not investigated histologically in a large series of GP or NSGP.[4] There is only a single case report on EM in perilesional epithelial cells in NSGP.[4] The presence of relatively expressed EM around foci of chronic inflammation, dilated prostatic glands, and ducts in NSGP is a mechanism of phenotypic cellular adaptation towards the new changes in prostatic tissue due to persistent active inflammation.[4] In this report, we describe the second case of coexistence of NSGP with EM. Unlike other authors,[10] we demonstrate focal and weakly false-positive reactivity for P504S.

NSGP-associated foci of EM shows negative chromogranin expression and weakly false-positive P504S immune staining. They are surrounded by P63 positive basal cells. These findings differ from the chromogranin+/P504S+ (strongly)/P63 immune profile of PCLC - foci in PCa [5] and confirm the benign EM - phenotype.

   Conclusion Top

In conclusion, it is important to recognize the association of NSGP with foci of benign EM and PCa (with or without PCLC) of the prostate. We assume that the combination of NSGP with both EM and PCa has not been reported in medical literature so far. We suggest such histological investigations to be performed in a large series of prostatic materials in order to clarify: On one hand the frequency and significance of EM in NSGP, and on the other hand - the differential diagnosis of EM with neuroendocrine PCLC in PCa.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Val-Bernal JF, Zaldumbide L, Garijo MF, González-Vela MC. Nonspecific (idiopathic) granulomatous prostatitis associated with low-grade prostatic adenocarcinoma. Ann Diagn Pathol 2004;8:242-6.  Back to cited text no. 1
Murugan P, Brown RE, Zhao B. Nonspecific granulomatous prostatitis with prostatic adenocarcinoma. Indian J Pathol Microbiol 2010;53:152-4.  Back to cited text no. 2
[PUBMED]  [Full text]  
Cheng L, MacLennan GT, Abdul-Karim FW, Lopez-Beltran A, Montironi R. Eosinophilic metaplasia of the prostate: A newly described lesion distinct from other eosinophilic changes in prostatic epithelium. Anal Quant Cytol Histol 2008;30:226-30.  Back to cited text no. 3
Dikov D, Vassilev I, Dimitrakov J. Nonspecific granulomatous prostatitis with calculous ductal ectasia and extensive Paneth cell-like epithelial metaplasia. Case report. APMIS 2005;113:564-7.  Back to cited text no. 4
Ablakha H, Bostwick DG. Paneth cell-like changes in prostatic adenocarcinoma represent neuroendocrine differentiation: Report of 30 cases. Hum Pathol 1994;25:135-9.  Back to cited text no. 5
Epstein JI, Hutchins GM. Granulomatous prostatitis: Distinction among allergic, nonspecific, and post-transurethral resection lesions. Hum Pathol 1984;15:818-25.  Back to cited text no. 6
Oppenheimer JR, Kahane H, Epstein JI. Granulomatous prostatitis on needle biopsy. Arch Pathol Lab Med 1997;121:724-9.  Back to cited text no. 7
Presti B, Weidner N. Granulomatous prostatitis and poorly differentiated prostate carcinoma. Their distinction with the use of immunohistochemical methods. Am J Clin Pathol 1991;95:330-4.  Back to cited text no. 8
Weaver MG, Abdul-Karim FW, Srigley JR. Paneth cell-like change of the prostate. Arch Pathol Lab Med 1992;116:1101-2.  Back to cited text no. 9
Iczkowski KA. Paneth cell-like change in benign prostate can account for P504S (AMACR) reactivity. Int J Clin Exp Pathol 2014;7:3454-5.  Back to cited text no. 10

Correspondence Address:
Maria Stoyanova Koleva
Department of General and Clinical Pathology, Medical University - Plovdiv, Bul., Vasil Aprilov 15A, Plovdiv
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_130_16

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

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