NKX3.1 is a prostatic tumor suppressor gene located on chromosome 8p. Although most studies have shown that staining for NKX3.1 protein is positive in the majority of primary prostatic adenocarcinomas, it has been shown to be downregulated in many high-grade prostate cancers, and completely lost in the majority of metastatic prostate cancers (eg, in 65% to 78% of lesions). A recent study showed that NKX3.1 staining with a novel antibody was highly sensitive and specific for high-grade prostatic adenocarcinoma when compared with high-grade urothelial carcinoma. This raised the question that this antibody may perform better than earlier used antibodies in metastatic prostate tumors. However, the sensitivity and specificity for prostate carcinomas for this antibody in metastatic lesions was not determined. Although prostate-specific antigen (PSA) and prostatic-specific acid phosphatase (PSAP) are excellent tissue markers of prostate cancer, at times they may be expressed at low levels, focally, or not at all in poorly differentiated primary and metastatic prostatic adenocarcinomas. The purpose of this study was to determine the performance of NKX3.1 as a marker of metastatic adenocarcinoma of prostatic origin. Immunohistochemical staining against NKX3.1, PSA, and PSAP was carried out on a tissue microarray (TMA) (0.6-mm tissue cores) of hormone naïve metastatic prostate adenocarcinoma specimens from lymph nodes, bone, and soft tissue. To determine the specificity of NKX3.1 for prostatic adenocarcinoma, we used TMAs that contained cancers from various sites including the urinary bladder, breast, colon, salivary gland, stomach, pancreas, thyroid, and central nervous system, and standard paraffin sections of cancers from other sites including the adrenal cortex, kidney, liver, lung, and testis. Overall 349 nonprostatic tumors were evaluated. Any nuclear staining for NKX3.1 was considered positive and the percentage of cells with nuclear staining and their mean intensity level were assessed visually. Sensitivity was calculated by considering a case positive if any TMA core was positive. The sensitivity for identifying metastatic prostatic adenocarcinomas overall was 98.6% (68/69 cases positive) for NKX3.1, 94.2% (65/69 cores positive) for PSA, and 98.6% (68/69 cores positive) for PSAP. The specificity of NKX3.1 was 99.7% (1/349 nonprostatic tumors positive). The sole positive nonprostatic cancer case was an invasive lobular carcinoma of the breast. NKX3.1 seems to be a highly sensitive and specific tissue marker of metastatic prostatic adenocarcinoma. In the appropriate clinical setting, the addition of IHC staining for NKX3.1, along with other prostate-restricted markers, may prove to be a valuable adjunct to definitively determine prostatic origin in poorly differentiated metastatic carcinomas.

Focal atrophy is extremely common in prostate specimens. Although there are distinct histologic variants, the terminology is currently nonstandardized and no formal classification has been tested for interobserver reliability. This lack of standardization hampers the ability to study the biologic and clinical significance of these lesions. After informal and formal meetings by a number of the authors, focal atrophy lesions were categorized into 4 distinct subtypes as follows: (i) simple atrophy, (ii) simple atrophy with cyst formation, (iii) postatrophic hyperplasia, and (iv) partial atrophy. In phase 1 of the study, pathologists with varying levels of experience in prostate pathology were invited to view via the Internet a set of "training" images with associated descriptions of lesions considered typical of each subtype. In phase 2 of the study, each participant provided diagnoses on a series of 140 distinct "test" images that were viewed over the Internet. These test images consisted of the 4 subtypes of atrophy and images of normal epithelium, high grade prostatic intraepithelial neoplasia, and carcinoma. The diagnoses for each image from each pathologist were compared with a set of "standard" diagnoses and the kappa statistic was computed. Thirty-four pathologists completed both phases of the study. The interobserver reliability (median kappa) for classification of lesions as normal, cancer, prostatic intraepithelial neoplasia, or focal atrophy was 0.97. The median kappa for the classification of atrophy lesions into the 4 subtypes was 0.80. The median percent agreement with the standard diagnosis for the atrophy subtypes were: simple 60.6%, simple with cyst formation 100%; postatrophic hyperplasia 87.5%; partial atrophy 93.9%. The lower percentage for simple atrophy reflected a propensity to diagnose some of these as simple atrophy with cyst formation. Seven pathologists completed the phase 2 analysis a second time, and their intraobserver reproducibility was excellent. Three of 4 pathologists with low agreement with the standard diagnosis for simple atrophy improved their scores after repeating the analysis after re-examination of the "training set" of images. In conclusion, these criteria for variants of focal prostate atrophy may facilitate studies to examine the relation between various patterns of prostate atrophy and prostate cancer.

Testicular carcinoid tumors are rare with only limited studies. We identified 29 primary testicular carcinoid cases from 7 academic institutions. Patients ranged in age from 12 to 65 years old (mean 36). The most common presenting symptom was the sole finding of either a testicular mass or swelling seen in 15/24 cases with available information. The next most common mode of presentation was as an incidental finding seen in 6 cases. Two patients had carcinoid syndrome including diarrhea, hot flashes, and palpitations. Nineteen were pure carcinoid tumors, 3 were associated with cystic teratoma, 2 with cysts lacking epithelial lining, 4 with epidermoid cyst, and 1 with dermoid cyst. The mean size was 2.5 cm. All 29 primary carcinoids lacked associated intratubular germ cell neoplasia, unclassified type. Mitotic figures were rare in primary carcinoid tumors with only 3 cases showing more than 2 per 10 HPF; necrosis was found in only 1 case. Random scattered mild to moderate nuclear atypia was seen in 12/29 cases. Of the 28 cases found premortem, treatment included focal excision in 3 patients and radical orchiectomy in 25 patients. Follow-up, available in 24 cases, ranged from 1 to 228 months (mean 52.7 mo); of the 20 patients with testicular typical carcinoid tumors found premortem, all were alive at last follow-up without recurrences or metastases. Of the 4 patients with a primary atypical carcinoid tumor, 1 at the time of diagnosis had retroperitoneal and lung metastases who after chemotherapy underwent resection of the retroperitoneal tumor showing metastatic yolk sac tumor and embryonal carcinoma. After resection, serum AFP levels remained elevated and the patient is scheduled for salvage chemotherapy and bone marrow transplant. The other 2 patients with atypical carcinoid and follow-up had no evidence of disease at 68 and 114 months. Most primary carcinoid tumors of the testis have a benign clinical course even if associated with epidermoid/dermoid cysts, or histologically mature teratoma. However, lesions with the morphology of atypical carcinoid can occasionally exhibit metastatic spread.

We studied 29 cases of basal cell carcinoma of the prostate including what others call adenoid cystic carcinoma of the prostate. Patients' age ranged from 42 to 89 (mean 69) years. The most common methods of diagnosis was transurethral resection (TURP) (n=29) and needle biopsy (n=9). In 28/29 cases, slides were reviewed and 24 (86%) cases showed more than 1 pattern: adenoid cysticlike (AC-P) pattern and small solid nests with peripheral palisading were the most predominant patterns, each seen in 18 cases (64%). Other patterns included: basal cell hyperplasialike in 9 cases (32%); small tubules occasionally lined by a hyaline rim in 9 cases (32%), with 4 of these cases also demonstrating intermingling cords of cells; and large solid nests in 8 cases (28.5%), 5 of which had central necrosis. Fourteen cases of small nests and tubules were centrally lined by eosinophilic cells. Desmoplasia was noted in 20 (71%) cases. Infiltration around benign glands was seen in 10 (36%) cases, with predominantly small nests and AC-P. Invasion of thick muscle bundles of the bladder neck was seen in 10 of 21 TURP cases. Perineural invasion was noted in 3 cases with AC-P and 1 case of small basaloid nests. Perineural and vascular invasion was seen in 2 basal cell carcinomas with large basaloid nests. Mitoses ranged from 0 to 60/10 hpf (mean=4). bcl2 was diffusely positive in 22/24 (92%) cases. Ki67 ranged from 2% to 80% (mean=23%). Ki67 > or =20% was seen in 13 (56.5%) cases, including all patterns except small solid nests. Basal cell markers (HMWCK, p63) either: (1) highlighted multiple layers of cells in 15/25 (60%) cases with sparing of the inner most luminal layer; (2) labeled just the outermost layers in 6/25 (24%) cases; or (3) reacted with only a few scattered cells in 4/25 (16%) cases (3 with large solid nests with central necrosis, 1 with tubules and cords). Seven patients had RP with: 5/7 showing extraprostatic extension with 1/5 also showing seminal vesicle involvement and 2/5 also with a positive margin; 1/7 having organ confined disease; and 1/7 showing no residual disease. An additional 11 cases showed extraprostatic extension on TURP with bladder neck invasion (n=10) or periprostatic adipose tissue invasion (n=1). Of 29 (65.5%) cases, 19 had follow-up > 1 year with a mean of 4.3 years (1 to 19 y). Of 19 (77%) cases, 14 had no evidence of disease after 1 to 19 (mean 5.8) years. Of 19 patients, 4 locally recurred with 2 after TURP, 1 after enucleation, and 1 after RP. Metastases developed in 4/29 patients: 1 in lung, 1 in lung and liver, 1 in lung, bone and liver, 1 in penile urethra. Basal cell carcinomas are rare tumors with a broad morphologic spectrum. These tumors predominantly show an indolent course with local infiltrative behavior. A small subset behaves aggressively with local recurrences and distant metastases. The most common morphology among those with an aggressive behavior is large solid nests more often with central necrosis, high Ki67%, and less staining with basal cell markers.