WHO 2022 classification of penile and scrotal cancers: updates and evolution

Squamous cell carcinoma (SCC) is the most common malignant tumour of the penis. The 2022 WHO classification reinforces the 2016 classification and subclassifies precursor lesions and tumours into human papillomavirus (HPV)-associated and HPV-independent types. HPV-associated penile intraepithelial neoplasia (PeIN) is a precursor lesion of invasive HPV- associated SCC, whereas differentiated PeIN is a precursor lesion of HPV-independent SCC. Block-type positivity of p16 immunohistochemistry is the most practical daily utilised method to separate HPVassociated from HPVindependent penile SCC. If this is not feasible, the term SCC, not otherwise specified (NOS) is appropriate. Certain histologies that were previously classified as "subtypes" are now grouped, and coalesced as "patterns", under the rubric of usual type SCC and verrucous carcinoma (e.g. usual-type SCC includes pseudohyperplastic and acantholytic/pseudoglandular carcinoma, and carcinoma cuniculatum is included as a pattern of verrucous carcinoma). If there is an additional component of the usual type of invasive SCC (formerly termed hybrid histology), the tumour would be a mixed carcinoma (e.g. carcinoma cuniculatum or verrucous carcinoma with usual invasive SCC); in such cases, reporting of the relative percentages in mixed tumours may be useful. The consistent use of uniform nomenclature and reporting of percentages will inform the refinement of future reporting classification schemes and guidelines/recommendations. The classification of scrotal tumours is provided for the first time in the fifth edition of the WHO Blue book, and it follows the schema of penile cancer classification for both precursor lesions and the common SCC of the scrotum. Basal cell carcinoma of the scrotum may have a variable clinical course and finds a separate mention.

Dataset for the reporting of urinary tract carcinoma-biopsy and transurethral resection specimen: recommendations from the International Collaboration on Cancer Reporting (ICCR)

The International Collaboration on Cancer Reporting (ICCR) is an alliance of major pathology organisations in Australasia, Canada, Europe, United Kingdom, and United States of America that develops internationally standardised, evidence-based datasets for the pathology reporting of cancer specimens. This dataset was developed by a multidisciplinary panel of international experts based on previously published ICCR guidelines for the production of cancer datasets. It is composed of Required (core) and Recommended (noncore) elements identified on the basis of literature review and expert consensus. The document also includes an explanatory commentary explaining the rationale behind the categorization of individual data items and provides guidance on how these should be collected and reported. The dataset includes nine required and six recommended elements for the reporting of cancers of the urinary tract in biopsy and transurethral resection (TUR) specimens. The required elements include specimen site, operative procedure, histological tumor type, subtype/variant of urothelial carcinoma, tumor grade, extent of invasion, status of muscularis propria, noninvasive carcinoma, and lymphovascular invasion (LVI). The recommended elements include clinical information, block identification key, extent of T1 disease, associated epithelial lesions, coexistent pathology, and ancillary studies. The dataset provides a structured template for globally harmonized collection of pathology data required for management of patients diagnosed with cancer of the urinary tract in biopsy and TUR specimens. It is expected that this will facilitate international collaboration, reduce duplication of effort in updating current national/institutional datasets, and be particularly useful for countries that have not developed their own datasets.

Validation of International Society of Urological Pathology (ISUP) grading for prostatic adenocarcinoma in thin core biopsies using TROG 03.04 'RADAR' trial clinical data

In 2014 a consensus conference convened by the International Society of Urological Pathology (ISUP) adopted amendments to the criteria for Gleason grading and scoring (GS) for prostatic adenocarcinoma. The meeting defined a modified grading system based on 5 grading categories (grade 1, GS 3+3; grade 2, GS 3+4; grade 3, GS 4+3; grade 4, GS 8; grade 5, GS 9-10). In this study we have evaluated the prognostic significance of ISUP grading in 496 patients enrolled in the TROG 03.04 RADAR Trial. There were 19 grade 1, 118 grade 2, 193 grade 3, 88 grade 4 and 79 grade 5 tumours in the series, with follow-up for a minimum of 6.5 years. On follow-up 76 patients experienced distant progression of disease, 171 prostate specific antigen (PSA) progression and 39 prostate cancer deaths. In contrast to the 2005 modified Gleason system (MGS), the hazards of the distant and PSA progression endpoints, relative to grade 2, were significantly greater for grades 3, 4 and 5 of the 2014 ISUP grading scheme. Comparison of predictive ability utilising Harrell's concordance index, showed 2014 ISUP grading to significantly out-perform 2005 MGS grading for each of the three clinical endpoints.

[Vancouver classification of renal tumors: Recommendations of the 2012 consensus conference of the International Society of Urological Pathology (ISUP)]

The 2012 consensus conference of the International Society of Urological Pathology (ISUP) has formulated recommendations on classification, prognostic factors and staging as well as immunohistochemistry and molecular pathology of renal tumors. Agreement was reached on the recognition of five new tumor entities: tubulocystic renal cell carcinoma (RCC), acquired cystic kidney disease-associated RCC, clear cell (tubulo) papillary RCC, microphthalmia transcription factor family RCC, in particular t(6;11) RCC and hereditary leiomyomatosis-associated RCC. In addition three rare forms of carcinoma were considered as emerging or provisional entities: thyroid-like follicular RCC, succinate dehydrogenase B deficiency-associated RCC and anaplastic lymphoma kinase (ALK) translocation RCC. In the new ISUP Vancouver classification, modifications to the existing 2004 World Health Organization (WHO) specifications are also suggested. Tumor morphology, a differentiation between sarcomatoid and rhabdoid and tumor necrosis were emphasized as being significant prognostic parameters for RCC. The consensus ISUP grading system assigns clear cell and papillary RCCs to grades 1-3 due to nucleolar prominence and grade 4 is reserved for cases with extreme nuclear pleomorphism, sarcomatoid and/or rhabdoid differentiation. Furthermore, consensus guidelines were established for the preparation of samples. For example, agreement was also reached that renal sinus invasion is diagnosed when the tumor is in direct contact with the fatty tissue or loose connective tissue of the sinus (intrarenal peripelvic fat) or when endothelialized cavities within the renal sinus are invaded by the tumor, independent of the size. The importance of biomarkers for the diagnostics or prognosis of renal tumors was also emphasized and marker profiles were formulated for use in specific differential diagnostics.

Solitary Intestinal Fibromatosis with Perinatal Bowel Obstruction

Three newborn male infants presented with bowel obstruction in the first day of life and at surgery were found to have solitary tumors involving the small or large intestine. Histologic examination in each case showed a transmural infiltrative spindle cell lesion having the morphologic features of fibromatosis. Ultrastructural studies in one case revealed the tumor to be composed of myofibroblasts. The patients are all alive and well without recurrences 26 months to 10 years after surgery. Only 3 previous cases of solitary congenital fibromatosis of the intestinal tract have been reported. Some of the other congenital spindle cell tumors cited in the literature under various names have morphologic and biologic similarities to our cases and may in fact be examples of congenital fibromatosis. The appropriate treatment of this unusual lesion is local excision, and the prognosis is excellent.

Leiomyosarcoma of urinary bladder following cyclophosphamide therapy: report of two cases

Leiomyosarcoma of urinary bladder is rare, although it is the most common mesenchymal tumor in adults. We report two cases of this tumor following cyclophosphamide therapy. The first case is from a 53-year-old man with Wegener's granulomatosis treated for 6 years with cyclophosphamide. He presented with painless hematuria, and the initial biopsy of the bladder tumor revealed a malignant spindle cell neoplasm. A final diagnosis of leiomyosarcoma was made on radical cystoprostatectomy. The second example is from a 21-year-old man who had received cyclophosphamide in early infancy for a bilateral retinoblastoma. He also presented with painless hematuria, and a bladder tumor was resected transurethrally and diagnosed as leiomyosarcoma. He underwent partial cystectomy two months later. Cyclophosphamide, when used for a neoplastic or non-neoplastic condition, is associated with an increased risk of developing bladder cancer. The distribution of histologic subtypes differs from that seen in spontaneous bladder tumors. A review of the literature shows an increased proportion of squamous cell carcinomas and sarcomas, especially leiomyosarcomas in cyclophosphamide exposed patients. Acrolein, a cytotoxic metabolite of cyclophosphamide excreted in urine, is regarded as the most likely causative agent.

Dermoid cyst of the testis: a study of five postpubertal cases, including a pilomatrixoma-like variant, with evidence supporting its separate classification from mature testicular teratoma

It is controversial if the rare dermoid cyst of the testis should be classified as a variant of mature teratoma or separately. The spectrum of findings is also ill defined, as is the relationship of dermoid cyst to intratubular germ cell neoplasia of the unclassified type (IGCNU). This study therefore reports the findings in five testicular dermoid cysts that occurred in five patients, 17-42 years of age, who presented with testicular masses. Four lesions consisted of a keratin-filled cyst with a thickened wall, whereas one had islands of "shadow" squamous epithelial cells with superimposed calcification and ossification (pilomatrixoma-like variant). Hair was identified grossly in two cases. On microscopic examination, four tumors had hair follicles with sebaceous glands showing a typical, cutaneous-type orientation to an epidermal surface, although no hair shafts were present in two. In addition, the fibrous wall contained smooth muscle bundles (all tumors) and eccrine or apocrine sweat glands (4 tumors). In some cases there were also glands lined by ciliated epithelium (4 tumors, including the pilomatrixoma-like variant), intestinal mucosa (1 tumor), and bone (2 tumors). There was no cytologic atypia or apparent mitotic activity, and no case had IGCNU in the seminiferous tubules. All patients were clinical stage I and were treated by orchiectomy without adjuvant therapy. All were well on follow-up from 1.5 to 9.5 years later. This study supports that dermoid cyst may have noncutaneous teratomatous elements and that an important criterion for its diagnosis is the absence of IGCNU. It also supports that it should be categorized separately from mature testicular teratoma because of the malignant nature of the latter in postpubertal patients. These observations suggest that there are at least two pathways for testicular teratomas in postpubertal patients: the more common being through IGCNU by differentiation from an invasive malignant germ cell tumor and the less common one, taken by dermoid cyst, by direct transformation from a nonmalignant germ cell.

Primary extrapulmonary sugar tumor (PEST): a report of four cases

The cell of origin and direction of differentiation of the clear cell tumor of the lung (the so-called sugar tumor) remains enigmatic. Recognition of HMB-45 immunoreactivity and identification of melanosomes have suggested a relationship to angiomyolipoma of kidney or liver and lymphangiomyoma. This has given rise to the concept that clear cell tumors are neoplasms of so-called perivascular epithelioid cells--PEComas. Herein we report the existence of four similar tumors occurring in extrapulmonary sites, one of which had malignant features. The three benign tumors occurred in females ages 9, 20, and 40 years; two were located in the rectum and one in the vulva. The malignant tumor occurred in the inter-atrial cardiac septum of a 29-year-old man. Common histologic features were a richly vascular organoid architecture, tumor cells with clear to pale eosinophilic cytoplasm, abundant glycogen, and immunoreactivity for HMB 45, but not S100, multiple keratin, neuroendocrine, or muscle markers. Benign tumors demonstrated low mitotic activity, no necrosis, and good circumscription; the malignant tumor showed considerable mitotic activity, necrosis, and an infiltrative growth pattern. Ultrastructurally, glycogen was present, mitochondria were abundant, and membrane-bound lamellated bodies consistent with premelanosomes were present in two cases, and equivocal in one. Because these tumors have light microscopic, immunohistochemical, and electron microscopic features similar to pulmonary sugar tumors, we propose the name primary extrapulmonary sugar tumor (PEST) for them. Although most PEST's are probably benign, malignant forms appear to exist. These cases further support the concept of a family of systemic HMB-45 positive tumors that include sugar tumors, angiomyolipoma of kidney or liver, lymphangiomyomas, and clear-cell myomelanocytic tumors of the falciform ligament/ligamentum teres.

Mixed epithelial and stromal tumor of the kidney lacks the genetic alterations of cellular congenital mesoblastic nephroma

Mixed epithelial and stromal tumor of the kidney is a recently recognized neoplasm that occurs almost exclusively in perimenopausal women. Because it frequently contains areas of smooth muscle in which epithelial structures are embedded, some have concluded that it is the adult form of congenital mesoblastic nephroma. Others have concluded that the morphology and epidemiology of mixed epithelial and stromal tumor indicate that it is unrelated to congenital mesoblastic nephroma. Although the genetic alterations of mixed epithelial and stromal tumor have not been previously elucidated, much is known about the genetic alterations of cellular congenital mesoblastic nephroma. The present study was undertaken to determine if mixed epithelial and stromal tumors have any of the genetic alterations recognized as typical of cellular congenital mesoblastic nephroma. RNA extraction was performed on formalin-fixed, paraffin-embedded tissue from 7 mixed epithelial and stromal tumors followed by reverse-transcription polymerase chain reaction to detect the ETV6-NTRK3 gene fusion. Fluorescent in situ hybridization with centromere-specific probes for chromosomes 8, 11, and 17 was performed to evaluate polyploidy of these chromosomes in 11 cases of mixed epithelial and stromal tumor. None of the mixed epithelial and stromal tumors showed any of these genetic alterations. We conclude that mixed epithelial and stromal tumor of the kidney lacks the genetic alterations typical of cellular congenital mesoblastic nephroma, is unrelated to it, and the appellation "adult mesoblastic nephroma" should not be used for these tumors.

The paratesticular region: histoanatomic and general considerations

The paratesticular region includes the testicular collecting system, the testicular tunics, and spermatic cord. For the purpose of discussion in this issue, the rete testis is also considered part of the paratestis, although it is principally intratesticular in location. The embryologic origins of the paratesticular components and their detailed anatomic and histologic features are presented to provide a background to better understand the pathologic processes affecting the paratestis. A wide variety of cysts, hyperplasias, neoplasms, and tumor-like conditions may affect the paratesticular region, at times resulting in challenging problems in differential diagnosis. An approach to the paratesticular causes of an intrascrotal mass lesion is presented.

Mesothelial lesions of the paratesticular region

Mesothelial lesions involving the paratesticular region include mesothelial cysts, reactive mesothelial hyperplasia, adenomatoid tumors, benign cystic mesothelioma, well-differentiated papillary mesothelioma, and malignant mesothelioma. The diagnosis and management of these lesions are often difficult for surgical pathologists, surgeons, and oncologists alike. Mesothelial lesions are relatively uncommon and most benign and malignant tumors present as testicular tumors with no specific findings. A preoperative diagnosis of malignancy is rarely made, and there is no established effective therapy for malignant mesothelioma. This article reviews the clinicopathologic features of paratesticular mesothelial lesions with emphasis in their differential diagnosis and prognosis.

Intrarenal schwannoma: a report of four cases including three cellular variants

Renal schwannomas are extraordinarily rare neoplasms; only six have been reported, the majority of which occurred in the renal pelvis. We report the clinical and pathologic features of four additional cases. The resected kidney in all patients contained a well-demarcated, yellow-tan, smooth, and bulging intraparenchymal tumor (mean size, 9.7 cm; range, 4 to 16 cm). Microscopically, three cases were classified as cellular schwannomas, and one was a usual-type schwannoma, with degenerative nuclear atypia. By immunohistochemistry, all tumors were strongly S-100 protein positive and negative for pan-cytokeratin, CD57, smooth muscle actin, desmin, and CD34. Epithelial elements were not noted in the tumors, and there was no history of any clinical syndromes in these patients. Analysis of the four cases showed the mean age at presentation to be 47 years (range, 18 to 84 years), with no sex predisposition (two men, two women). Most patients were asymptomatic, and all received a diagnosis of renal cell carcinoma and treated as having such. Recognition and awareness of these rare, benign tumors will assist in the differential diagnosis of spindle cell tumors of the kidney and prevent their misdiagnosis as sarcomatoid carcinomas of the kidney or renal sarcomas. Our study, the largest series to date of renal schwannomas, demonstrates a predilection for the cellular variant in the kidney, documents that these tumors may present in the nonhilar region of the kidney, and provides clinical evidence of their benign biologic behavior.

Mixed epithelial and stromal tumor of the kidney

We describe the clinicopathologic features of 12 patients with a distinctive tumor of the kidney characterized by a mixture of epithelial and stromal elements that form solid and cystic growth patterns. Similar tumors were reported previously in the literature under various names, including adult mesoblastic nephroma. All but one of the patients were women. The only man had a long history of treatment with lupron and diethylstilbesterol. Seven of the women had histories of long-term oral estrogen use of whom six had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy several years prior, and the seventh patient had been using oral contraceptives for many years. Another woman had this operation but did not receive any hormone therapy. Ages ranged from 31 to 71 years (mean, 56 yrs). Six patients presented with symptoms, including pain and infections attributable to mass effect, and in six the tumor was detected incidentally. Grossly, the tumors were well-circumscribed (mean size, 6 cm; range, 3-12 cm) and consisted of solid and cystic components, most often in equal proportions but in variable distribution. Microscopically, the spindle cell component ranged in appearance from scar-like fibrous tissue to leiomyoma-like interlacing fascicles; usually there was a mixture of both. More cellular foci reminiscent of ovarian stroma or solitary fibrous tumor were also present. No blastema was present. Epithelial elements (composed of clusters of tubules with variable lining) were scattered amidst the spindle cells, and focally transformed into large cysts lined by cells with abundant pink cytoplasm and a hobnail appearance. Immature epithelial elements typical of Wilms' tumor were not present. Muscle markers (desmin and smooth muscle actin) were positive diffusely and strongly in the spindle cells of all tumors, whereas HMB-45 and CD34 were absent. Estrogen receptors were detected in the nuclei of spindle cells in seven tumors and progesterone receptors in three. The distinctive clinicopathologic characteristics of these lesions warrant their classification as a separate category of kidney tumor. We suggest the descriptive term "mixed epithelial and stromal tumor" for this group until its nature and relationship to other kidney lesions are further clarified. Its preponderance in females with a history of long-term estrogen replacement and the history of long-term sex-steroid use in the only male patient, combined with the frequent content of estrogen and progesterone receptors in the spindle cells, suggest that the hormonal milieu plays a role in the evolution of these tumors. The clinical and pathologic parallels with mucinous cystic tumors of pancreas and liver raise the possibility of a common pathogenetic mechanism that may be linked to the periductal fetal mesenchyme. We think this entity is a benign composite neoplasm in which stroma and epithelium are both integral neoplastic components.

Prognostic factors in prostate cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, a multidisciplinary group of clinicians, pathologists, and statisticians considered prognostic and predictive factors in prostate cancer and stratified them into categories reflecting the strength of published evidence and taking into account the expert opinions of the Prostate Working Group members.

MATERIALS AND METHODS

Factors were ranked according to the previous College of American Pathologists categorical rankings: category I, factors proven to be of prognostic importance and useful in clinical patient management; category II, factors that have been extensively studied biologically and clinically but whose importance remains to be validated in statistically robust studies; and category III, all other factors not sufficiently studied to demonstrate their prognostic value. Factors in categories I and II were considered with respect to variations in methods of analysis, interpretation of findings, reporting of data, and statistical evaluation. For each factor, detailed recommendations for improvement were made. Recommendations were based on the following aims: (1) increasing uniformity and completeness of pathologic evaluation of tumor specimens, (2) enhancing the quality of data collected pertaining to existing prognostic factors, and (3) improving patient care.

RESULTS AND CONCLUSIONS

Factors ranked in category I included preoperative serum prostate-specific antigen level, TNM stage grouping, histologic grade as Gleason score, and surgical margin status. Category II factors included tumor volume, histologic type, and DNA ploidy. Factors in category III included perineural invasion, neuroendocrine differentiation, microvessel density, nuclear roundness, chromatin texture, other karyometric factors, proliferation markers, prostate-specific antigen derivatives, and other factors (oncogenes, tumor suppressor genes, apoptosis genes, etc).

Primary malignant melanoma of the urethra: a clinicopathologic analysis of 15 cases

The clinical and pathologic features of 15 primary urethral melanomas occurring in patients (nine women and six men) age 44 to 96 years (mean age, 73 yrs) are described. In the men the tumor involved the distal urethra. In eight women it involved the distal urethra, usually the meatus; both the distal and proximal urethra were involved in one woman. The tumors were typically polypoid and ranged from 0.8 to 6 cm (mean, 2.6 cm) in maximum dimension. A vertical growth phase was present in all tumors, with a prominent nodular component in seven of them. A radial growth phase was seen in nine tumors. The depth of invasion ranged from 2 to 17 mm. The tumors had diffuse, nested, storiform, or mixed growth patterns. The neoplastic cells typically had abundant eosinophilic cytoplasm, large nuclei with prominent nucleoli, and brisk mitotic activity. Melanin pigment was seen in 12 tumors but was conspicuous in only six. At the time of diagnosis, 13 tumors were confined to the urethra and two patients had lymph node metastasis. Nine patients died of disease 13 to 56 months after initial diagnosis and treatment, and one patient had a local recurrence at 4 years and subsequently died of sepsis 1 year later. Three patients were alive and well at 11 months, 23 months, and 7 years. One patient died at the time of the initial operation, and one died of a ruptured aortic aneurysm at 3 years without evidence of melanoma at autopsy. Primary malignant melanomas of the urethra, one fifth of which are amelanotic, must be included in the differential diagnosis of a number of primary neoplasms that involve the urethra, including transitional cell carcinoma, sarcomatoid carcinoma, and sarcomas. Conventional prognostic factors, such as depth of invasion or tumor stage, do not seem to play as important a role in predicting survival as the mucosal location and the nodular growth present frequently in these tumors.

Sex cord-stromal tumors of the testis with entrapped germ cells: a lesion mimicking unclassified mixed germ cell sex cord-stromal tumors

The authors describe 10 sex cord-stromal tumors of the testis that incorporated germ cells, thereby mimicking the unclassified type of mixed germ cell sex cord-stromal tumor (MGCSCST). These neoplasms occurred in patients from 3 to 48 years old (mean age, 26 years) who presented with testicular masses. On microscopic examination, nine tumors had a combination of tubular and cord-like arrangements of sex cord cells with transition to spindle-shaped tumor cells. They were diagnosed as either unclassified sex cord-stromal tumors (n = 5) or Sertoli-stromal cell tumors (n = 4). One tumor was a pure Sertoli cell tumor. The admixed germ cells were usually at the periphery and in clusters, but occasionally were in the center or more diffuse. In nine patients the germ cells resembled spermatogonia, having round nuclei with uniform, dusty chromatin and inconspicuous or small nucleoli. None of these cells stained with a variety of markers used for neoplastic germ cells, and in one case in which the non-neoplastic Sertoli cells were strongly reactive for inhibin but the neoplastic Sertoli cells were not, all the germ cells within the tumor occurred adjacent to inhibin-positive Sertoli cells. With static cytophotometry, a diploid deoxyribonucleic acid content was found in these germ cells in the two investigated cases. In one case the germ cells had the morphologic appearance of seminoma cells and they stained positively for the markers of neoplastic germ cells. This case was interpreted as a "collision" tumor between a Sertoli cell tumor and a seminoma. The authors conclude that sex cord-stromal tumors with entrapped germ cells of the testis are more common than unclassified MGCSCSTs--a bona fide testicular example of which has not been seen by any of the authors.

Renal oncocytosis: a morphologic study of fourteen cases

Diffuse renal involvement by numerous oncocytic nodules has rarely been described. We report 14 cases (19 specimens) with innumerable oncocytic nodules in the kidney. Invariably, these kidneys showed additional associated findings. We suggest the term renal oncocytosis for this entire morphologic spectrum. Six (43%) cases had histologically or radiologically proven bilateral involvement. Each specimen had at least one dominant tumor (2.0-10.5 cm) in addition to numerous other microscopic to macroscopic oncocytic nodules. Additional features observed were: interstitial pattern, with the oncocytic tubules and acini diffusely intermingling with and infiltrating between non-neoplastic parenchyma (one case); diffuse oncocytic change in the nonneoplastic tubules, cytologically difficult to separate from the oncocytic nodules (seven cases); and benign oncocytic cortical cysts (four cases). The dominant mass in 13 specimens was a renal oncocytoma and in two, a chromophobe renal cell carcinoma. In four specimens, the largest tumor was considered a hybrid tumor because of the presence of mixed histologic features of both tumor types. Most smaller nodules had the morphologic features of renal oncocytoma, but a few had the appearance of chromophobe renal cell carcinoma or nodules with hybrid features. We conclude that the presence of numerous oncocytic nodules may be associated with a wide spectrum of oncocytic changes in the kidney. The association of numerous renal oncocytoma-like nodules with lesions having a mixed morphology or a morphology of pure chromophobe renal cell carcinoma suggests that they may constitute a morphologic spectrum of oncocytic tumors and that renal oncocytoma and chromophobe renal cell carcinoma may arise from a common progenitor lesion.

Postatrophic hyperplasia of the prostate gland: a detailed analysis of its morphology in needle biopsy specimens

Postatrophic hyperplasia is a histologic pattern showing atrophic and hyperplastic glands, sometimes with a small acinar configuration. Because distinction from small acinar carcinoma may be challenging, particularly in needle biopsy specimens, we studied 56 needle biopsy specimens containing 68 foci to ascertain the morphologic spectrum of postatrophic hyperplasia. All foci showed a distinct lobular small acinar proliferation with varying proportions of atrophic and hyperplastic glands. Gland size was typically variable, predominantly of small caliber but occasionally of intermediate to larger caliber. Round, oval, elongated, slitlike and stellate glands were seen. The nuclei were generally regular without hyperchromasia, with rare small nucleoli seen in 10 (15%) foci. The cytoplasm was variable, ranging from scant in atrophic glands to moderate or abundant and clear or occasionally eosinophilic in hyperplastic glands. An irregular internal gland contour was noted in glands with features of both atrophy and hyperplasia. Basal cells were apparent by light microscopy in most foci, although their distribution within foci and between foci varied. This finding was confirmed in all 26 cases studied with the high molecular weight cytokeratin immunohistochemical stain (34betaE12). Associated pathology included adenocarcinoma (12%), high-grade prostatic intraepithelial neoplasia (3%), atrophy distinct from foci of postatrophic hyperplasia (55%), and atypical adenomatous hyperplasia (2%). Adjunctive features of cancer were not seen in any of the foci of postatrophic hyperplasia. Familiarity with the histologic features of postatrophic hyperplasia will allow its confident separation from cancer, especially in limited biopsy material.

Collecting duct carcinoma of kidney

Collecting duct carcinoma of the kidney is a rare neoplasm with only approximately 100 cases described in the literature to date. The tumor occurs in a wide age range and predominantly in males. Typical collecting duct carcinoma consists of a grossly infiltrative neoplasm centered on the renal medulla. The usual histological pattern is that of a tubular or tubulopapillary carcinoma with a desmoplastic stroma that often contains neutrophils. Less commonly, collecting duct carcinoma has a papillary architecture with desmoplasia and infiltrative growth. Collecting duct carcinoma spread aggressively and many patients have metastases at the time of presentation. Origin in the collecting duct is suggested by medullary location, dysplasia of the epithelium in collecting ducts outside the tumor, and reactivity with antibody to high molecular weight cytokeratin and Ulex europaeus agglutinin. No unifying cytogenetic or molecular genetic features have been discovered thus far. The concept of collecting duct carcinoma is expanding and should include the recently described renal medullary carcinoma that is associated with sickle cell trait.

Large cell calcifying Sertoli cell tumor of the testis: contrasting features of six malignant and six benign tumors and a review of the literature

We report six malignant and six benign large cell calcifying Sertoli cell tumors of the testis and compare the features of malignant and benign cases based on these cases and those in the literature. All the tumors in this report consisted of sheets, nests, solid tubules, and cords of eosinophilic cells, with focal calcifications, as well as a substantial neutrophilic infiltrate in 11 of them. Analysis of our cases and those in the literature showed that the malignant tumors were unilateral and solitary and occurred at a mean age of 39 years (range 28-51 years), whereas the benign neoplasms were bilateral and multifocal in 28% of cases and occurred at a mean age of 17 years (range 2-38 years). Only one malignant tumor occurred in a patient with evidence of a genetic syndrome (Carney syndrome), whereas 36% of benign tumors had various genetic syndromes or endocrine abnormalities. Most of the tumors in the latter cases were bilateral and multifocal. There were strong associations of malignant behavior with size >4 cm, extratesticular growth, gross or microscopic necrosis, high-grade cytologic atypia, vascular space invasion, and mitotic rate greater than three mitoses per 10 high-power fields. All malignant cases exhibited at least two of these features, whereas all benign cases lacked any of them. The presence of any one of these features in a solitary large cell calcifying Sertoli cell tumor, especially in a patient >25 years of age, should be viewed as suspicious for malignant behavior, whereas the presence of two or more of these features indicates a strong probability of a malignant course. "Low" percentages (< or =35%) of tumor cells staining for proliferating cell nuclear antigen (PCNA) also may correlate with benign behavior, but some benign tumors have high PCNA values. Ki-67 values (MIB-1 antibody) did not correlate with biologic behavior, nor did immunostains for p53 protein.

The Heidelberg classification of renal cell tumours

This paper presents the conclusions of a workshop entitled 'Impact of Molecular Genetics on the Classification of Renal Cell Tumours', which was held in Heidelberg in October 1996. The focus on 'renal cell tumours' excludes any discussion of Wilms' tumour and its variants, or of tumours metastatic to the kidneys. The proposed classification subdivides renal cell tumours into benign and malignant parenchymal neoplasms and, where possible, limits each subcategory to the most commonly documented genetic abnormalities. Benign tumours are subclassified into metanephric adenoma and adenofibroma, papillary renal cell adenoma, and renal oncocytoma. Malignant tumours are subclassified into common or conventional renal cell carcinoma; papillary renal cell carcinoma; chromophobe renal cell carcinoma; collecting duct carcinoma, with medullary carcinoma of the kidney; and renal cell carcinoma, unclassified. This classification is based on current genetic knowledge, correlates with recognizable histological findings, and is applicable to routine diagnostic practice.

Granulocytic sarcoma of the female genital tract: a clinicopathologic study of 11 cases

Eleven patients, 13 to 76 (mean, 40) years of age, had granulocytic sarcoma of the female genital tract (FGT) (ovary, seven cases; vagina, three cases; cervix, one case). In nine cases, the FGT involvement was the initial clinical presentation of the disease, and in the other two cases, the FGT involvement was discovered during a relapse of acute myeloid leukemia. The tumors ranged from 0.5 to 14 (mean, 7.5) cm in greatest dimension. Two ovarian tumors were bilateral, and three were green. Microscopic examination revealed a predominantly diffuse pattern of growth, but cords and pseudoacinar spaces were also present focally in several cases. Sclerosis was seen in five tumors and was prominent in one. Prominent myeloid differentiation was readily recognizable on routinely stained sections in three cases, whereas the neoplastic cells in the other cases were primitive with only rare eosinophilic myelocytes. All 11 tumors were positive for chloroacetate esterase, nine of nine were strongly and diffusely positive for lysozyme, eight of eight for myeloperoxidase, seven of seven for CD68, and six of six for CD43. Examination of bone marrow or peripheral blood performed after the diagnosis of FGT involvement revealed acute myeloid leukemia in three of five cases. Two of these patients died of disease, 1 and 16 months after the initial diagnosis, and the third, who received chemotherapy, is alive and free of disease 8 months after the initial diagnosis. One of the two patients with negative bone marrow had recurrent granulocytic sarcoma 30 months after diagnosis and died of sepsis 1 month later; no residual disease was noted at autopsy. The other patient is alive and free of disease 18 months after the diagnosis. One of the four remaining patients with primary FGT involvement who did not have a bone marrow biopsy died of leukemia 24 months later; no follow-up information is available for the other three patients. One of the two patients with a prior diagnosis of acute myeloid leukemia was alive with disease 26 months later; follow-up is not available for the second patient. The diagnosis was often difficult in these cases, the most common problem being distinction from malignant lymphoma, but carcinoma, granulosa cell tumor, and, rarely, other tumors were considered. Immunohistochemical and enzyme histochemical staining were useful in establishing the diagnosis, although suspicion of the diagnosis on examination of routinely stained sections was of paramount importance.

Granulocytic sarcoma of the testis: a report of two cases of a neoplasm prone to misinterpretation

We report the cases of two men, aged 48 and 71 years, with granulocytic sarcoma of the testis. Both presented with left testicular swelling and underwent orchiectomy, which revealed cream-colored to yellow-tan, rubbery-to-firm, testicular tumors with extensive paratesticular spread. The tumor in the younger patient was composed of a uniform population of primitive cells with scant cytoplasm and was initially misinterpreted as malignant lymphoma. Staging revealed no extrascrotal spread. The patient was treated with radiation and chemotherapy and remained free of disease for 12 years, at which time he died of unrelated causes. The older patient had a history of a myelodysplastic syndrome. His tumor contained cells with bright eosinophilic, occasionally granular cytoplasm, consistent with myeloid lineage. Because of a prominent component of myelocytes, with round, eccentric nuclei and moderately abundant cytoplasm, and because of an associated chronic inflammatory cell infiltrate that contained mature plasma cells, the tumor was initially misinterpreted as a plasmacytoma, although it was reinterpreted as a granulocytic sarcoma before initiation of therapy. Tumor cells in both cases were positive with a chloroacetate esterase stain. Immunohistochemical staining revealed expression of myeloperoxidase, lysozyme, leukocyte common antigen, and CD43, but not of B-cell-specific or T-cell-specific antigens in both cases. Granulocytic sarcomas are apt to be misinterpreted as other hematolymphoid tumors, which may result in a significant error in management. The diagnosis should at least be thought of any time the diagnosis of malignant lymphoma or plasmacytoma of the testis is being considered.

Paratesticular serous papillary carcinoma. A report of six cases

Six intrascrotal, invasive epithelial neoplasms of serous papillary type arose in the paratesticular region of patients 16 to 42 (mean, 30.8) years of age. Five patients, one with an associated hydrocele, presented with a testicular mass and one with a hydrocele only. The serum CA-125 level was elevated in one of the two patients in whom it was measured. Grossly, the tumors were solid, white, or tan, poorly circumscribed, often gritty masses. Four tumors involved primarily the soft tissue between the testis and epididymis (testiculoepididymal groove) and one, the paratesticular soft tissue. The sixth tumor was confined to the visceral tunica vaginalis at the inferior pole of the testis. The most common microscopic pattern was characterized by invasive, well-formed papillae lined by serous cuboidal or columnar cells with eosinophilic cytoplasm and malignant nuclear features. Psammoma bodies were abundant in all the cases. Areas of borderline serous tumor were present in two tumors and predominated in one. Five of five tumors were positive for keratin (AE1/3), S-100, epithelial membrane antigen, and Ber-EP4; three of five for Leu M1 and B72.3; two of five for carcinoembryonic antigen and placental alkaline phosphatase; and one in five for vimentin. Ultrastructural examination in one case demonstrated gland formation with delicate luminal microvilli and cilia. Follow-up information was available in five cases: Three patients are without evidence of disease after relatively short postoperative intervals of 1, 1, and 3 years, although one of these patients has had a persistently elevated CA-125 level. Two patients had recurrence of their tumors 4 and 7 years after diagnosis, one with diffuse abdominal spread, the other in a cervical lymph node. The latter patient died of his disease 5 years after diagnosis.

Distribution of lipochrome pigment in the prostate gland: biological and diagnostic implications

Lipochrome pigment is characteristically found in Wolffian duct-derived structures including seminal vesicles and ejaculatory ducts. The presence of lipochrome pigment is helpful in identifying atypical histological patterns of seminal vesicle or ejaculatory duct that mimic prostatic adenocarcinoma. The authors studied the distribution of lipochrome pigment in 28 radical prostatectomy specimens using a modified Ziehl-Neelson stain and fluorescence microscopy. In all cases secretory epithelium of the central zone contained lipochrome pigment often in significant amounts (2 to 3+). Secretory epithelium from peripheral and transition zones in each of four specimens (14.3%) contained lipochrome pigment. In addition, occasional examples of nodular hyperplasia, prostatic intraepithelial neoplasia, and prostatic adenocarcinoma contained lipochrome pigment. The preferential distribution of lipochrome pigment in central zone epithelium adds further support to the hypothesis that central zone glands are derived embryologically from Wolffian duct (mesoderm) rather than urogenital sinus (endoderm), which gives rise to transition and peripheral zone glands. Furthermore, lipochrome pigment should not be used as the sole diagnostic criterion for separating atypical histological patterns of seminal vesicle and ejaculatory duct from those of prostatic origin.

Epstein-Barr virus is detected in undifferentiated nasopharyngeal carcinoma but not in lymphoepithelioma-like carcinoma of the urinary bladder

The Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC) and with lymphoepithelioma-like carcinomas developing in certain anatomic sites. In this study, an in situ hybridization was used to identify EBV-encoded ribonucleic acid (RNA) (EBER1) transcripts in 32 of 45 cases of NPC but not in any of the 11 lymphoepithelioma-like carcinomas developing in the urinary bladder. EBER1 was most commonly detected in those NPCs having undifferentiated or nonkeratinizing squamous histology rather than the keratinizing squamous cell subtype of NPC. The EBV-encoded latent membrane protein 1 (LMP1) was expressed focally in only seven of 21 EBER1-positive NPCs by an immunohistochemical technique. These findings imply that EBER1 hybridization is more sensitive than LMP1 immunohistochemistry on paraffin sections in detecting carcinoma-associated virus. Previous in vitro studies have suggested that LMP1 expression might be a function of differentiation, but this study of naturally infected NPCs showed no strong correlation between LMP1 positivity and degree of tumor differentiation, albeit a limited spectrum of differentiation that could be examined. In two cases in which frozen tissue was available, the NPCs were monoclonal with respect to viral DNA structure, implying that the virus was present before malignant transformation. Unlike NPCs, the lymphoepithelioma-like carcinomas of the bladder were uniformly EBV negative, lending further evidence to the growing body of literature linking EBV with lymphoepithelial carcinomas of foregut-derived tissues but not with similar-appearing tumors developing in other anatomic sites.

Recognition of renal actinomycosis: nephrectomy can be avoided. Report of a case

Nephrectomy is performed for the diagnosis and treatment of renal actinomycosis. A cachectic 62-year-old man with a left renal mass underwent exploration and needle biopsy of the mass. No malignant disease was found. When his condition further deteriorated, the kidney was re-explored. Numerous biopsies intraoperatively finally revealed actinomycosis, so the operation was terminated with preservation of the kidney. Long-term treatment with antibiotics was begun with immediate, marked improvement in the patient's condition. At 1 year the renal mass had almost resolved. This is the first reported case of the diagnosis and treatment of renal actinomycosis without nephrectomy.

Renal oncocytoma and granular renal cell carcinoma. A comparative clinicopathologic and DNA flow cytometric study

Twenty-three renal oncocytomas and 18 granular renal cell carcinomas (GRCC) were comparatively studied clinicopathologically and by DNA flow cytometry to delineate their differences. Of the patients with renal oncocytomas, 15 were men and 8 were women, and their ages ranged from 42 to 81 years (mean, 64 years). The gross appearance of renal oncocytomas was characteristically homogeneous tan-brown, with variable scarring, without areas of large hemorrhage, and with no apparent necrosis. Twenty-two renal oncocytomas were confined within the kidney (Robson stage I) and one tumor extended into the renal vein (stage IIIa). Twenty-two renal oncocytomas, including the stage IIIa tumor, manifested diploid DNA content and only one neoplasm showed a feature suggestive of near-diploid DNA aneuploidy. Of the 17 patients with renal oncocytomas who had adequate follow-up, none developed metastasis or died of disease. Of the patients with GRCC, 13 were men and 5 were women, and their ages ranged from 30 to 73 years (mean, 53 years). The gross appearance of GRCC was variegated, yellow to tan, and punctuated with geographic areas of necrosis. Eleven patients with GRCC were stage I, 4 were stage II, 2 were stage IIIa, and 1 patient had metastases at initial examination (stage IV). Seven GRCCs were DNA diploid, one was DNA tetraploid, and 10 tumors were DNA aneuploid. Twelve patients were alive with no evidence of disease (12 to 36 months; median, 26 months). All patients with DNA diploid neoplasm pursued benign clinical courses. One patient was alive with metastatic disease and two patients developed metastases and died of their disease; all three patients had DNA aneuploid tumors. Two patients died of other causes and one patient was lost to follow-up. Our data indicate that renal oncocytoma is a distinct clinicopathologic disease with characteristic gross, histologic, DNA flow cytometric, and biologic features that are different from GRCC.

A lineage-specific t(1;14)(q21;q32) as an early event in development of B-cell clonal expansion

We report a patient in whom a cell line of 47,XY,+X,t(1;14)(q21;q32) constitution was found in a lymph node excised from the neck. Histologic examination and immunophenotyping both in situ and by flow cytometry failed to confirm a diagnosis of B-cell lymphoma, but Southern analysis indicated the presence of B-cell clonal expansion. These observations support the concept that primary chromosomal abnormalities occur in clonal expansions in the very earliest stages of tumorigenesis.

Paneth cell-like change and small cell carcinoma of the prostate. Two divergent forms of prostatic neuroendocrine differentiation

Paneth cell-like change of the prostate refers to collections of prostatic cells with eosinophilic cytoplasmic granules that bear a striking histological resemblance to normal intestinal Paneth cells. Paneth cell-like change in malignant prostatic epithelium usually represent neuroendocrine differentiation, with neuroendocrine granules confirmed by immunohistochemical and ultrastructural studies. We report the histopathological, immunohistochemical, and electron microscopic findings in a mixed adenocarcinoma with Paneth cell-like change and small cell undifferentiated carcinoma. This case illustrates two divergent forms of neuroendocrine differentiation occurring in a single prostatic neoplasm. The spectrum of neuroendocrine differentiation in the prostate should be expanded to include tumors with Paneth cell-like change in addition to carcinoid tumors and small cell undifferentiated carcinoma. These three distinct forms of prostatic neuroendocrine neoplasia appear to correlate with three size ranges of neuroendocrine granules seen by electron microscopy.

Prostatic tissue in mature cystic teratomas of the ovary

We report two examples of mature cystic teratomas of the ovary containing prostatic tissue. Both were incidental findings in teratomas that were otherwise typical at clinical and pathologic levels. The prostatic tissue contained ducts and acini in a simple branching pattern similar to that seen in the peripheral zone of the prostate gland. Transitional cell elements were present in both cases and compact acini resembling Cowper's gland were noted in one. No testicular or Wolffian duct tissue was noted. The immunohistochemical staining pattern of the glands was identical to that seen in normal prostate. In a literature review, four additional cases were identified. The presence of prostatic tissue in a 46XX tumor suggests induction by locally produced androgen. Some investigators have identified luteinized stromal cells and indicated these as the source of this androgen. Other possible androgenic origins include ovarian hilar cells, adrenal cortex, and tumor cells.

Prostate cancer presenting with malignant ascites: signet-ring cell variant of prostatic adenocarcinoma

A case of prostate cancer presenting with malignant ascites as the sole clinical manifestation is reported. The clinical course simulated occult gastrointestinal malignancy. At the histologic level, the tumor had a signet-ring morphology. Detailed immunocytochemical and ultrastructural studies, however, confirmed the prostatic origin of this neoplasm. Signet-ring carcinoma of the prostate is a rare aggressive form of prostatic cancer which may present with a malignant effusion and may mimic gastrointestinal cancer.

Mediastinal large-cell lymphoma

The records of 20 patients with pathologically diagnosed mediastinal large-cell lymphoma with sclerosis, a recently documented but uncommon subtype of mediastinal non-Hodgkin's lymphoma, were retrospectively reviewed to determine the clinical and radiologic features of the condition at the time of presentation. The disease was staged according to the Ann Arbor classification: 15 patients presented in clinical stage I or II and 5 in clinical stage III or IV. The patients, 6 women and 14 men, ranged in age from 15 to 63 years (mean = 31 years). Chest pain (experienced by 10 patients), dyspnea (by 9) and cough (by 7) were the most common clinical features. Obstruction of the superior vena cava occurred in seven patients. The mediastinal masses were large (the mean diameter was 10.8 cm) and located anteriorly (prevascularly). They contained low-attenuation areas and were often associated with other sites of mediastinal adenopathy. The initial pathologic diagnosis was incorrect for eight patients (40%). Mediastinal large-cell lymphoma can be added to the differential diagnosis of a large anterior mediastinal mass with obstruction of the superior vena cava.

Sclerosing adenosis of the prostate gland. A lesion showing myoepithelial differentiation

Sclerosing adenosis of the prostate is a rare lesion characterized by the proliferation of variably sized glands in a cellular stroma. We report light microscopic, immunohistochemical, and ultrastructural studies in 22 examples from 15 patients. Two cases were identified in 100 consecutive prostates embedded by a whole organ method, giving a prevalence of 2%. Antibodies directed against the following antigens were used: high-molecular-weight cytokeratin (CKH; 34 beta E12); cytokeratin (CK; AE1/AE3), prostatic acid phosphatase (PAP), prostate-specific antigen (PSA), S-100 protein, muscle-specific actin (HHF35), and vimentin (Vim). Cells within the glandular component demonstrated positive reactivity for CK, CHH, PSA, and PAP, indicating a prostatic epithelial origin. In addition, a distinct population of cells reacting for muscle-specific actin and S-100 protein was identified within this glandular element. Adequate material for ultrastructural study was available in five cases; all showed the presence of flattened cells located between the basement membrane and secretory epithelial cells, which had features typical for myoepithelial differentiation. Although the prostate gland does not normally contain myoepithelial cells, we have documented their consistent presence in this unusual lesion; we believe these cells arise by a metaplastic process from the prostatic basal cells.

Adenomatous hyperplasia of the rete testis. A clinicopathologic study of nine cases

Adenomatous hyperplasia of the rete testis is an uncommon lesion that has recently been described. Nine cases of adenomatous hyperplasia were identified in two institutions from 1980 to 1989. At diagnosis the nine patients ranged in age from 30 to 74 years (mean, 59 years; median, 66 years). Three patients presented with a grossly identifiable solid or cystic testicular hilar mass. In six cases adenomatous hyperplasia was an incidental microscopic finding--five from orchiectomy specimens and one from an autopsy specimen. Microscopically, the hyperplasia consisted of a tubulopapillary epithelial proliferation of rete testis. The lining cells were cuboidal to low columnar and lacked nuclear pleomorphism or mitotic figures. The involvement of the rete testis was predominantly diffuse. In seven cases the seminiferous tubules showed atrophic changes. Ultrastructural and immunohistochemical (keratin, epithelial-membrane antigen: positive; vimentin, muscle-specific actin, desmin, and S-100: negative) studies done on one case showed similar features to those of nonhyperplastic rete testis epithelium. No patient with adenomatous hyperplasia showed local recurrence or metastasis. Possible pathogeneses include hormonal imbalance or stimulatory influence that remains as yet unidentified.

In situ adenocarcinoma ex pleomorphic adenoma of the lacrimal gland

We report a unique case of in situ adenocarcinoma ex pleomorphic adenoma of the lacrimal gland. The patient is alive and disease-free 2 1/2 years after complete local excision of the tumour. The current clinicopathologic status of this unusual tumour is discussed in the context of the reported experience to date.

Basal epithelial cells of human prostate gland are not myoepithelial cells. A comparative immunohistochemical and ultrastructural study with the human salivary gland

The hypothesis that basal epithelial cells of the human prostate are of myoepithelial origin was investigated using immunohistochemical and ultrastructural methodologies. The immunohistologic analyses show significant phenotypic differences between prostatic basal cells and myoepithelial cells of the salivary gland. Although both cell types stain intensely with the 312C8-1 monoclonal antibody, only true myoepithelial cells demonstrated significant amounts of muscle-specific actin as decorated by the HHF35 monoclonal antibody. Furthermore, using double-labeling experiments, the prostatic basal cells were strongly decorated with a fluorescein-tagged basal cell-specific keratin but were negative with the rhodamine-tagged phalloidin, a chemical that binds specifically to actin microfilaments. Ultrastructural studies also showed an absence of thin microfilament bundles, dense bodies, and micropinocytotic vesicles in the prostatic basal cells. The current investigations show that the prostatic acini do not have a basal myoepithelium. Although some authors have suggested a stem cell role for prostatic basal cells, the weight of experimental work argues against this hypothesis. The exact role of the basal epithelial cells of the prostate is not known, although they may serve endocrine, paracrine, or other regulatory functions and may be involved in modulating signals between prostatic stroma and epithelium.

Basal epithelial cells of human prostate gland are not myoepithelial cells. A comparative immunohistochemical and ultrastructural study with the human salivary gland

The hypothesis that basal epithelial cells of the human prostate are of myoepithelial origin was investigated using immunohistochemical and ultrastructural methodologies. The immunohistologic analyses show significant phenotypic differences between prostatic basal cells and myoepithelial cells of the salivary gland. Although both cell types stain intensely with the 312C8-1 monoclonal antibody, only true myoepithelial cells demonstrated significant amounts of muscle-specific actin as decorated by the HHF35 monoclonal antibody. Furthermore, using double-labeling experiments, the prostatic basal cells were strongly decorated with a fluorescein-tagged basal cell-specific keratin but were negative with the rhodamine-tagged phalloidin, a chemical that binds specifically to actin microfilaments. Ultrastructural studies also showed an absence of thin microfilament bundles, dense bodies, and micropinocytotic vesicles in the prostatic basal cells. The current investigations show that the prostatic acini do not have a basal myoepithelium. Although some authors have suggested a stem cell role for prostatic basal cells, the weight of experimental work argues against this hypothesis. The exact role of the basal epithelial cells of the prostate is not known, although they may serve endocrine, paracrine, or other regulatory functions and may be involved in modulating signals between prostatic stroma and epithelium.

Transrectal fine-needle aspiration and truecut needle biopsy of the prostate: a blinded comparison of accuracy

Transrectal needle aspiration biopsy and core biopsy of the prostate were performed simultaneously on 88 men with prostatic nodules. Cytologic and histologic assessments were made in a blinded, independent fashion, and the results were compared. All patients with positive findings on aspiration also had positive findings on core biopsy, for a positive predictive value for aspiration of 100%. However, five negative and six "insufficient" results obtained by aspiration were positive on core biopsy, for a negative predictive value for aspiration of 88%. This experience support the use of needle aspiration as an initial diagnostic maneuver in the assessment of prostatic nodules.

Small-acinar patterns in the prostate gland with emphasis on atypical adenomatous hyperplasia and small-acinar carcinoma

A number of anatomic structures and pathophysiologic processes can mimic small-acinar carcinoma of the prostate gland. Seminal vesicles, ejaculatory ducts, and Cowper's glands can, at times, enter into the differential diagnosis of adenocarcinoma. Likewise atrophy, postatrophic hyperplasia, and some variants of central nodular hyperplasia can present a troubling small-acinar pattern. Another common proliferation referred to as atypical adenomatous hyperplasia lies on a morphologic continuum with low-grade acinar carcinoma and is thought by many investigators to be premalignant. Its distinction from minimal-deviation adenocarcinoma is made on the basis of both architectural and somewhat arbitrary nuclear criteria. When encountered alone, atypical adenomatous hyperplasia alerts the pathologist to examine all tissue, as it is a frequent accompaniment of well-differentiated adenocarcinoma. Once a diagnosis of low-grade acinar carcinoma has been made, accurate pathologic staging, especially in conjunction with clinically unsuspected disease (stage A), is extremely important in treatment planning and prognostication.

Atypical spindle cell lesions of the prostate

This report is a review of the spectrum of prostatic spindle cell lesions that are usually benign, but have morphologic features suggestive of high-grade malignancy. The problem is complicated further by the extreme rarity and heterogeneity of such lesions. Sixteen cases of atypical prostatic spindle cell proliferations are reported, and the differential diagnosis with malignancy is reviewed.

Selected ultrastructural aspects of urothelial and prostatic tumors

Ultrastructural techniques have been widely applied in the study of urothelial and prostatic tumors. In the common proliferative diseases affecting the lower urogenital tract, electron microscopy has provided us with a greater understanding of the pathobiology and morphology of these disease processes. Specific diagnostic application, however, has been limited. In the unusual tumors affecting urothelium and prostate such as neuroendocrine carcinoma, carcinosarcoma, and sarcomas, electron microscopy has provided some practical diagnostic information of value in patient management. This paper provides a survey of the fundamental and practical contributions of ultrastructural studies in the prostatic and urothelial areas.

The ultrastructure and histogenesis of male germ neoplasia with emphasis on seminoma with early carcinomatous features

The range of ultrastructural morphology was studied in 107 male germ cell neoplasm to assess relationships among tumor subtypes and to consolidate diagnostic criteria. Eighty-three pure-pattern neoplasms including 47 seminomas, 26 embryonal carcinomas, 10 endodermal sinus tumors, and 24 mixed germ cell tumors were analyzed. In the seminoma category, 4 cases showing cell surface specialization in keeping with early carcinomatous transformation were noted. The finding suggested a closer link between seminoma and nonseminomatous germ cell tumors than had been traditionally recognized and was in keeping with other clinical, histologic, biochemical, and xenograft observations. Subtypes of nonseminomatous germ cell tumors also exhibited a continuum of ultrastructural morphology with some types such as embryonal carcinoma and endodermal sinus tumor often blending together. At a practical level, electron microscopy has been of value in selected differential diagnoses such as seminoma versus lymphoma.

Diagnostic electron microscopy of male genital tract tumors

As illustrated in this review, neoplasms of the male genital tract are markedly heterogenous, reflecting their complex embryologic derivation and histogenetic classification. Transmission electron microscopy has greatly increased our understanding of the structure of these tumors, and in doing so has greatly improved our light microscopy. Additionally, in a number of selected situations, TEM also provides important practical diagnostic information. Currently, light microscopy in conjunction with clinical information is the central tool of tumor taxonomy. However, TEM with histochemistry, immunohistology, analytic cytometry, and molecular biology provide practical and useful information in some situations. In all cases, the application of these techniques has greatly increased our overall understanding of tumor structure, pathobiology, and classification.