CASE REPORTS
CARCINOMA OF PROSTATE METASTATIC TO PAROTID GLAND RONALD HREBINKO, M.D. SUZANNE R. TAYLOR, M.D., PH.D. ROBERT R. BAHNSON, M.D.*
From the Division of Urologic Surgery and the Department Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
of
ABSTRACT-A rare case of prostate cancer with metastasis to the parotid salivary gland is reported. The prostatic origin of the mass was proven by incisional biopsy and immunohistochemical staining for prostate-specific antigen. Additional studies of the tumor included ultrastructural and quantitative deoxyribonucleic acid (DNA) analysis.
Parotid gland involvement with metastatic prostate cancer has been previously reported only twice. lo In one instance the diagnosis was made by a characteristic appearance on light microscopy with confirmation of the prostatic primary disease at autopsy. In the other report a similar histologic appearance of synchronous lesions of the prostate and parotid allowed the diagnosis. In the following patient a parotid mass was shown to be a metastasis from the prostate by the use of an immunoperoxidase stain for prostate-specific antigen. Case Report A sixty-nine-year-old black man with a history of Stage D2 prostate cancer presented with a hard left preauricular mass of six months’ duration. The painless growth of the fixed lesion paralleled a progressive left facial hypesthesia. A few firm cervical and inguinal nodes were present as well as massive hepatomegaly. Eight months previously a transurethral resection of the prostate was performed with an unsuspected pathologic diagnosis of poorly differentiated adenocarcinoma. The patient underwent pelvic irradiation and treatment with diethylstilbestrol. *Recipient of American Cancer Career Development Award 86-48.
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An incisional parotid biopsy showed metastatic adenocarcinoma, and radiographic studies demonstrated the presence of extensive osseous and visceral metastases. Bilateral orchiectomy was performed but a clinical response was not observed. The patient died three months later. Pathology The tumor was reddish tan and firm on gross inspection. The histologic appearance was that of an undifferentiated adenocarcinoma invading normal parotid tissue (Fig. 1). The nuclei histologically were pleomorphic with marked hyperchromatism. The tumor stained positively for intracytoplasmic prostate-specific antigen (Fig. 2) and negative for mucicarmine. Electron microscopy showed irregular nuclei with small nucleoli and an abundance of isometric intracytoplasmic secretory vacuoles containing light to moderately electron-dense material consistent with adenocarcinoma. Nuclear DNA content was determined on Feulgen-stained imprints of the tumor using the Cell Analysis Systems (Lombard, IL) Model 100 image analysis system.3*4 The GO/G1 population had a DNA index of 0.993 indistinguishable from a normal diploid DNA content, with 15.5 percent of cells in SGSM. The tumor had a high G2M component of 12.5 percent, and
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DNA Index 1
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DNA Content (pg) FIGURE 1. Poorly differentiated of prostate within parotid gland.
adenocarcinoma
FIGURE 3. Nuclear DNA content. GO/G1 population has DNA index of 0.993. Large G2M population seen at DNA index of 2.01.
have been documented.6.7 In only 2 previous cases metastasis to the parotid gland have been reported. Our patient’s tumor is the first to be proved with immunohistochemical methods and analyzed by DNA image analysis. A postmortem examination does not routinely include dissection of the parotid, and it is possible that the true incidence of involvement of the parotid by metastatic prostate cancer is greater than 3 reported cases would suggest . Pittsburgh, 2. Immunoperoxidase stain for prostatic specific antigen. Enzyme antigen stains brown.
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there were 5.9 percent
of cells with DNA con-
tents above the G2M peak correlating with the high degree of nuclear pleomorphism seen histologically (Fig. 3). Comment Most of the data on the natural history and spread of prostate cancer is derived from autopsy studies. 5 Lymph node and bone involvement are common, with the lungs, bladder, liver, and adrenals being the most frequent sites of solid organ metastases. Less commonly, metastases to the kidneys, pancreas, heart, thyroid, and even the hollow abdominal viscera
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References 1. Livolsi VA: Prostatic carcinoma presenting as a primary parotid tumor, Oral Surg, Oral Med, Oral Path01 48: 447 (1979). 2. Kucan JO, Frank DH, and Robson MC: Tumors metastatic to the parotid gland, Br J Plast Surg 34: 299 (1981). 3. Taylor SR, Titus-Ernstoff L, and Stitely S: Central values and variation of measured nuclear DNA content in imprints of normal tissues determined by image analysis, Cytometry 10: 382 (1989). 4. Bacus JW, and Grace LJ: Optical microscope system for standardized cell measurements and analyses, Applied Optics 26: 3280 (1987). 5. Kozlowski JM, and Grayhack JT: Carcinoma of the prostate, in Gillenwater JY, Grayhack JT, Howards SS, and Duckctt JW (Eds): Adult and Pediatric Urology, Chicago, Year Book Mcdical Publishers, 1987, pp 1146-1149. 6. Arnheim FK: Carcinoma of the prostate-a study of the post-mortem findings in one hundred and seventy-six cases, J Urol 60: 599 (1948). 7. Saitoh J, et aE: Metastatic patterns of prostate cancer-correlation between sites and numbers of organs involved, Cancer 54: 3078 (1984).
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