Chia Sui Kao

Solid pattern yolk sac tumor: a morphologic and immunohistochemical study of 52 cases.

Yolk sac tumors may exhibit numerous patterns. One that has received little attention overall, yet is not uncommon, is a solid pattern, which is especially prone to misinterpretation, usually as seminoma, in biopsy specimens from metastatic or mediastinal sites. This distinction is of critical importance as the 2 tumors are treated differently. To determine features useful in the diagnosis of solid yolk sac tumor we reviewed 52 germ cell tumors (28 testicular primaries, 21 metastases from the testis, and 3 mediastinal primaries) that had a yolk sac tumor component with foci of solid growth, defined as a sheet-like arrangement of tumor cells occupying >2 mm2 and with no or only rare microcysts. Solid yolk sac tumor was almost always associated with other patterns, most commonly microcystic/reticular (75%), glandular (35%), and myxoid (25%). The solid foci consisted of sheets of cells with usually abundant cytoplasm that was mostly (85%) pale to clear and frequently had intercellular basement membrane deposits (75%), rare microcysts (67%), significant nuclear pleomorphism (65%), and hyaline globules (65%). In 2 cases (4%), the cells were small with scant cytoplasm (blastema-like variant). A myxoid background (39%), lymphocytic infiltrate (17%), and an appliqué pattern (8%) were sometimes observed. On immunostaining, AE1/AE3 cytokeratin and glypican 3 provided the most intense and diffuse reactivity for solid yolk sac tumor, whereas &agr;-fetoprotein was negative in 38%. CD117 stained 59%, whereas only rare cells in 1 case (3%) were weakly reactive for podoplanin; OCT3/4 was uniformly negative. We conclude that solid yolk sac tumor can generally be recognized by careful morphologic evaluation, especially its association with other yolk sac tumor patterns, the presence of intercellular band-like deposits of basement membrane, occasional microcysts, nuclear pleomorphism, intracellular hyaline globules, and usual absence of lymphocytes. In difficult cases a concise immunohistochemical panel consisting of AE1/AE3, glypican 3, and OCT3/4 distinguishes solid yolk sac tumor from other neoplasms. &agr;-fetoprotein stains are commonly negative or weak and focal in solid yolk sac tumor and cannot be solely relied on for diagnosis. Common CD117 positivity in solid pattern yolk sac tumors makes it an unreliable discriminator between yolk sac tumor and seminoma.

Nonchoriocarcinomatous Trophoblastic Tumors of the Testis: The Widening Spectrum of Trophoblastic Neoplasia.

Tumors of trophoblastic derivation other than choriocarcinoma are very rare in the testis but have been reported on occasion in association with other germ cell tumors. Their morphologic spectrum is analogous to the trophoblastic tumors of the female genital tract including epithelioid trophoblastic tumor (ETT) and placental site trophoblastic tumor (PSTT). Herein we report our experience with 8 cases of trophoblastic tumors of testicular origin that lacked the features of choriocarcinoma; these included 4 ETTs, 1 PSTT, 1 unclassified trophoblastic tumor (UTT), 1 partially regressed choriocarcinoma with a monophasic morphology, and 1 hybrid tumor showing a mixture of adenocarcinoma and a UTT. All tumors occurred in young men 19 to 43 years old. Five arose de novo within the testis (2 ETTs, 1 UTT, 1 regressing choriocarcinoma, and the hybrid tumor) as a component of mixed germ cell tumors, and 3 (2 ETTs and 1 PSTT) were found in metastatic sites after chemotherapy. The trophoblastic component was minor (5% to 10%) in 6 tumors but was 95% of 1 metastatic tumor (ETT) and 50% of the hybrid tumor. Other germ cell tumor elements were identified in all cases, most commonly teratoma. The ETTs consisted of nodules and nests of squamoid trophoblast cells showing abundant eosinophilic cytoplasm, frequent apoptotic cells, extracellular fibrinoid material, and positivity for p63 and negativity for human placental lactogen (HPL). The PSTT showed sheets of discohesive, pleomorphic, mononucleated trophoblast cells that invaded blood vessels with fibrinoid change and were p63 negative and HPL positive. The UTT showed a spectrum of small and large trophoblast cells, some multinucleated but lacking distinct syncytiotrophoblasts, and was patchily positive for both p63 and HPL. The hybrid tumor had ETT-like and adenocarcinomatous areas that coexpressed inhibin and GATA3 but were negative for p63 and HPL, leading to classification of the trophoblastic component as UTT. Seven of the patients were alive and well on follow-up (8 to 96 mo; median, 39 mo), whereas the patient with the hybrid tumor died of liver metastases at 2 years. Our study verifies that trophoblastic neoplasms often having the features of nonchoriocarcinomatous gestational trophoblastic tumors may arise from the testis, occur either in the untreated primary tumor or in metastases after chemotherapy, and should be distinguished from choriocarcinoma given what appears to be a less aggressive clinical course.

Testicular embryonal carcinoma: a morphologic study of 180 cases highlighting unusual and unemphasized aspects.

A total of 180 consecutive testicular cancers containing a component of embryonal carcinoma (EC) were reviewed to assess the morphologic features of the EC component. EC mostly (84%) occurred as a component of a mixed germ cell tumor, but 16% were pure. Solid (55%), glandular (17%), and papillary (11%) were the most common primary patterns (predominant architectural pattern occupying at least 50%), whereas other less common primary patterns included nested (3%), micropapillary (2%), anastomosing glandular (1%), sieve-like glandular (<1%), pseudopapillary (<1%), and blastocyst-like (<1%). Occasionally, EC developed predominantly in the context of polyembryoma-like (6%) and diffuse embryoma-like (“necklace” pattern) (3%) proliferations. In all, 69% had secondary architectural patterns, the most frequent being glandular (31%), papillary (14%), and solid (12%). An appliqué appearance, in which smudged and degenerate-appearing EC cells appear “applied” to the tumor periphery, was common (67%). EC cells with clear cytoplasm and distinct cell membranes (seminoma-like) were present in 11%, and dense lymphocytic infiltration and granulomatous inflammation were seen in 7% and 3%, respectively. Features simulating yolk sac tumor and teratoma were also seen: pseudoendodermal sinuses (34%), columnar cells (20%), and secretory-type subnuclear cytoplasmic vacuoles (6%). Syncytiotrophoblast cells were frequent (46%). Intratubular EC, typically partly necrotic and calcified, occurred in 24%. The associated stroma was more often non-neoplastic (53%) than neoplastic (29%). The rarity of some poorly characterized patterns of EC (micropapillary, blastocyst-like, anastomosing glandular, and sieve-like glandular) and some that overlap with those of other germ cell tumors, as well as some uncommon cytologic features, may result in misinterpretation, potentially impacting management. The association with other more common patterns and typical cytologic features, together with simple awareness of these variant morphologies, are helpful in establishing an accurate diagnosis of EC.

Gonadoblastoma: an immunohistochemical study and comparison to Sertoli cell nodule with intratubular germ cell neoplasia, with pathogenetic implications

To investigate the immunohistochemical properties of the sex cord cells of gonadoblastoma and Sertoli cell nodule with intratubular germ cell neoplasia unclassified (IGCNU) as a means of objective distinction and to provide insight into the pathogenesis.

The utility of immunostaining for NUT, GAGE7 and NY‐ESO‐1 in the diagnosis of spermatocytic seminoma

To identify specific positive immunohistochemical markers for spermatocytic seminoma (SS).

A case report of adrenocortical carcinosarcoma with oncocytic and primitive neuroectodermal-like features

Adrenocortical carcinosarcomas are rare aggressive neoplasms; only a few have been reported to date, all with dismal prognosis. These were reported as having varying morphology. We have encountered a case of adrenal carcinosarcoma with an undifferentiated component bearing similarities to primitive neuroectodermal tumors and other areas of oncocytic differentiation. The 48-year-old woman patient presented with abdominal pain and unintended, excessive weight loss. Computed tomographic imaging revealed a tumor located adjacent to the liver and kidney necessitating a partial nephrectomy and hepatectomy. Histologically, the tumor exhibited malignant features. Melan-A, inhibin, calretinin, cytokeratin AE1/AE3, synaptophysin, and neuron-specific enolase were positive immunohistochemically. The patient developed metastasis within 2 months of surgery and is currently alive with disease after chemotherapy. Adrenal carcinosarcoma is a rare highly aggressive malignancy with a wide morphologic spectrum. Recognition of variant morphology and applying correct immunohistochemical studies will aid in reaching an accurate diagnosis.

Juvenile granulosa cell tumors of the testis: a clinicopathologic study of 70 cases with emphasis on its wide morphologic spectrum.

The clinical and pathologic features of 70 juvenile granulosa cell tumors (JGCTs) of the testis are presented. The patients were from 30 weeks gestational age to 10 years old; 60 of 67 (90%) whose ages are known to us were 6 months old or younger. Sixty-two underwent gonadectomy, 6 wedge excision, and 2 only biopsy. Twenty-six tumors were left sided and 22 right sided. Six occurred in an undescended testis and 2 in dysgenetic gonads. The most common presentation was a testicular mass (65%), followed by an “enlarging testis” (25%). Six of 14 patients in whom it was measured had “elevated” serum &agr;-fetoprotein (AFP), likely physiologically, and 1 had gynecomastia. The tumors measured 0.5 to 5 cm (mean, 1.7 cm; median, 1.5 cm) and were most commonly well circumscribed and typically yellow-tan; approximately 2/3 had a cystic component, whereas 1/3 were entirely solid. Microscopic examination typically showed a lobular growth, punctuated in 67 cases by variably sized and shaped follicles containing material that was basophilic (21%), eosinophilic (44%), or of both characters (35%); 3 lacked follicles. In nonfollicular areas, the tumor cells typically grew diffusely but occasionally had a corded arrangement (26%) or reticular appearance (29%). The stroma was either fibrous or fibromyxoid; hemorrhage associated with hemosiderin-laden macrophages was focally seen in 16%. The tumor cells were mostly small to medium sized with round to oval nuclei containing inconspicuous nucleoli and moderate to abundant, but occasionally scant, pale to lightly eosinophilic, sometimes vacuolated, cytoplasm; nuclear grooves were infrequent (6%). Focal columnar morphology was seen in 27% of the tumors. Mitoses were plentiful in 37%, and apoptosis was prominent in 46%. Intratubular tumor was seen in 43% and entrapped seminiferous tubules in 70%. Lymphovascular invasion was present in 2 cases, rete testis involvement in 4, and necrosis in 1. Rare features/patterns included: regressed tumor with hyalinization and prominent blood vessels (13%), papillary growth (4%), basaloid morphology (1%), spindle cell predominance (1%), microcystic foci (1%), adult granulosa cell–like (1%) patterns, and hyaline globules (1%). Inhibin (16/18), calretinin (8/9), WT1 (6/7), FOXL2 (12/12), SF-1 (12/12), and SOX9 (6/11) were positive, whereas SALL4 and glypican-3 were consistently negative in the neoplastic granulosa cells. Only 1 of 10 tumors was focally positive for &agr;-fetoprotein. JGCT is a rare neoplasm with a wide morphologic spectrum that also occurs rarely in undescended testes and dysgenetic gonads. The solid and reticular patterns may pose diagnostic challenges, but the lobular appearance and follicular differentiation are characteristic. Immunohistochemical stains may aid in its distinction from other tumors of young male individuals, particularly yolk sac tumor, a neoplasm that peaks at a somewhat later age. Twenty-four patients with follow-up, including 4 of 6 patients treated with wedge resection/biopsy, had no evidence of disease (2 to 348 mo; mean, 83 mo; median, 61 mo). One additional patient was alive at 260 months, but the disease status is unknown. The benign clinical course of all cases of JGCT with follow-up, despite often frequent mitotic activity, supports testis sparing surgery when technically feasible.

Myoid Gonadal Stromal Tumor A Clinicopathologic Study of Three Cases of a Distinctive Testicular Tumor

OBJECTIVES To report three new cases of testicular myoid gonadal stromal tumor to better characterize its features. METHODS The clinicopathologic findings (including follow-up) were evaluated and a review of the literature was performed. RESULTS The patients were 38, 43, and 59 years old, and tumor sizes were 1.2, 1.3, and 3.2 cm. All were unilateral, well circumscribed, adjacent to the rete testis, and composed exclusively of spindled cells with elongated nuclei and occasional nuclear grooves arranged in fascicles with admixed variably ectatic blood vessels. Nucleoli were inconspicuous, and the cytoplasm was scant, ill-defined, and pale/lightly eosinophilic. No sex cord component was present. Mitotic figures ranged from zero to five per 10 high-power fields. Significant atypia, lymphovascular invasion, and necrosis were absent. All were consistently positive for smooth muscle actin, S100 protein, FOXL2, and steroidogenic factor 1 but negative for h-caldesmon, calretinin, and SOX9. Inhibin and calponin were focally positive. All patients were alive and well at 5, 31, and 58 months postorchiectomy. Combining our cases with those previously reported (n = 6) shows that this neoplasm occurs mostly in younger men (mean, 37 years), and all follow-up thus far (mean, 25 months) has been benign. CONCLUSIONS Myoid gonadal stromal tumors are small (<4 cm) indolent testicular tumors distinctly different from other sex cord-stromal tumors and are adequately managed by orchiectomy.

Nephrogenic adenomas in pediatric patients: a morphologic and immunohistochemical study of 21 cases.

Similar to nephrogenic adenomas in adults, those in children are rare benign lesions that often occur in the setting of previous surgery or chronic irritation of the urinary tract. These lesions often present with hematuria and/or as polypoid or papillary lesions on cystoscopy, which may indicate malignancy. We sought to evaluate the various patterns of nephrogenic adenoma occurring in the pediatric population and better characterize the immunophenotype of these lesions. We reviewed 21 cases of nephrogenic adenomas from urinary bladder biopsies of 16 patients. Most patients had a history of urinary bladder augmentation with recurrent urinary stones and urinary tract infections. Many cases presented as a papillary or polypoid mass on cystoscopy. The most common morphologic patterns are papillary, tubulocystic, and a mixed pattern of papillary and tubulocystic, followed by cystic and tubular. On immunostaining, PAX-2, PAX-8, CK7, and MUC-1 provided the most diffuse and intense positive reactivity for nephrogenic adenoma, whereas CD10 and P504S were focal and lesser in intensity when positive. p63 and PAX-5 were consistently negative. We conclude that, although rare in children, nephrogenic adenoma should be included in the differential diagnosis of papillary/polypoid lesions in the urinary tract, especially in the context of previous surgery, chronic irritation from recurrent urinary tract infections, or stones. The immunohistochemistry profile of nephrogenic adenomas in our study also provides evidence that these are derived from distal renal tubular cells. In difficult cases, an immunohistochemical panel consisting of cytokeratin 7, PAX-2, PAX-8, and MUC-1 may be useful.

Dissecting Gonadoblastoma of Scully: A Morphologic Variant That Often Mimics Germinoma.

Dr Robert E. Scully, who recognized and defined gonadoblastoma (GB), used the term “dissecting gonadoblastoma” (DGB) to describe variants with either an infiltrative type or diffuse pattern instead of the usual small nested arrangement. These patterns have not been emphasized in the literature. To investigate the features of DGB we examined 50 GBs microscopically and performed immunohistochemistry (IHC) in some. DGB was found in 38 (76%) GBs and was represented by 3 patterns. The most frequent was solid/expansile (n=26), consisting of large coalescent nests of germ cells, often (92%) interrupted by fibrovascular septa, with usually minor numbers of sex cord cells. Less frequent were small anastomosing nests (n=24) and cord-like arrangements (n=22) of germ cells irregularly distributed in a prominent stroma and with mostly inconspicuous sex cord cells. Most DGBs (24) showed >1 pattern and demonstrated the characteristic globular deposits of basement membrane, although these were often subtle. The germ cells in all patterns varied from spermatogonium-like to seminoma-like; OCT3/4 was positive only in the latter (7/7). The sex cord cells were small with dense, oval or angulated nuclei, inconspicuous nucleoli, and positivity for inhibin (9/9, strong), FOXL2 (9/9, strong), SF1 (8/9, strong), SOX9 (9/9, weak and focal), WT1 (5/7, variable), and calretinin (3/7, variable). Granulomas were present in 84% of germinoma foci, 13% of DGB foci, and 8% of classic GB foci. Twenty two of 38 DGBs had associated germinoma; 3 also had embryonal carcinoma, yolk sac tumor, and choriocarcinoma, respectively. Follow-up of 2 cases lacking an invasive tumor showed that both patients were disease free at 13 and 4.8 years after bilateral gonadectomy. We conclude that DGB is commonly seen with classic GB and displays identical IHC features, supporting it as a morphologic variant of GB. It appears likely that cord-like DGB is the earliest phase in a GB developmental continuum that may proceed successively into anastomosing, nested (classic GB), and solid/expansile patterns. DGB often mimics germinoma because of the large size of the nests, pseudoinfiltrative pattern of some cases, and inconspicuous sex cord cells. The presence of sex cord cells (identification aided by IHC for sex cord markers), the heterogenous morphology of the germ cells, and globules of basement membrane are useful differential features. The lack of a granulomatous reaction also favors DGB over germinoma. Mistaking DGB for GB with invasive germinoma may result in more aggressive therapy than warranted. The likely relationship of DGB to the relatively recently described concept of so-called “undifferentiated gonadal tissue” is discussed herein.