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The aim of the present work was to improve the understanding of the impact of malignancy grade and myogenic/rhabdomyoblastic differentiation on the natural course of retroperitoneal liposarcoma. All consecutive patients affected by primary well-differentiated (WD)/dedifferentiated (DD) retroperitoneal liposarcoma, surgically treated at our institution between January 2002 and December 2011, were retrospectively evaluated. Tumors were stained for mdm2 and 5 myogenic markers (smooth muscle actin-α, h-caldesmon, calponin, desmin, myogenin). The French National Federation of the Centers for the Fight Against Cancer (FNCLCC) grading system was applied. Overall survival, crude cumulative incidence of local recurrence, and distant metastases were calculated. Multivariable analyses were carried out. A total of 144 patients were identified. Median follow-up was 68 months (interquartile range: 46 to 104 mo). Fifty-two patients were affected by WD/G1 and 92 by DD liposarcoma. Among the latter, 60 were grade G2 and 32 G3. Myogenic differentiation was present in 54 cases (8/52 WD/G1, 27/60 DD/G2, 18/32 DD/G3). Seven cases had a rhabdomyoblastic DD component (1/60 DD/G2 and 6/32 DD/G3). Five-year overall survival rates were 93%, 57%, and 21% for WD/G1 liposarcoma, G2 DD, and G3 DD liposarcoma, respectively, and 75%, 42%, and 29% for liposarcoma without myogenic differentiation, with myogenic differentiation, with rhabdomyoblastic differentiation, respectively (P<0.001). Of note, 5/6 patients affected by G3 DD liposarcoma with a rhabdomyoblastic component died within 8 months. FNCLCC grade and myogenic differentiation significantly predicted the outcome of retroperitoneal liposarcoma. These should be factored into treatment decision-making and possibly used to stratify patients in clinical trials.

We describe 10 solitary fibrous tumors (SFT) with high-grade malignant overgrowth, all of which showed the presence of a synchronous or previous classic SFT/malignant SFT (MSFT) component. Seven were "dedifferentiated," with an abrupt transition from a classic SFT/MSFT to a high-grade component consisting of a nondistinctive high-grade sarcoma in 4 cases and divergent differentiation in 3. The nondistinctive high-grade component consisted of epithelioid and/or spindle cells often associated with overt pleomorphism or small round cell sarcomas. The divergent differentiation featured a rhabdomyosarcoma in 2 cases and an osteosarcoma in 1. Three cases (tentatively called "evolved") showed a gradual transition from classic SFT/MSFT to a nondistinctive high-grade sarcoma or presented features of high-grade sarcoma at the time of metastasis (assessed by fine-needle aspiration cytology) without any component suggesting a diagnosis of classic SFT/MSFT. The high-grade component showed loss of CD34 expression in half of the dedifferentiated SFTs and all of the dedifferentiated SFTs with divergent differentiation, whereas Ki-67 was markedly increased in all of the evaluable cases and paralleled the tumor grade. In 4 cases, the expression and phosphorylation status of key factors that control transcription and protein synthesis were also investigated. Both S6 and 4E-BP1 showed low activation in the low-grade MSFT and a high level of activation in the high-grade component. Seven of the 10 patients died of their disease during follow-up, with a median overall survival of 73 months (range, 5 to 288 mo). The median time to distant metastasis was 156 months after the initial diagnosis, and median overall survival from the first signs of metastasis was 8 months.

All of the members of the peripheral primitive neuroectodermal tumor family (Ewing sarcomas, neuroectodermal tumors of bone, peripheral neuroepitheliomas, and Askin tumors) have similar morphologic and immunophenotypical features (ie, the proliferation of small and medium-sized round cells in a fibrous background showing strong and diffuse immunohistochemical positivity for CD99), and the common cytogenetic abnormality of a nonrandom translocation involving the EWS gene and one of several members of the erythroblastosis virus transforming sequence family of transcription factors. The combination of clinical information and morphologic/immunophenotypical characteristics is usually sufficient for a correct diagnosis, but there are rare cases in which an unusual predominant or multidirectional immunophenotypical differentiation makes diagnosis a challenge and requires the use of molecular cytogenetic or molecular techniques. We describe 3 such cases in which we employed fluorescence in-situ hybridization analysis to detect translocation involving the EWS gene and reverse transcription polymerase chain reaction followed by sequencing to detect the fusion transcript EWS-FLI1.

Gastrointestinal stromal tumors (GISTs) are characterized by the presence of activating mutations affecting the c-Kit or the PDGFRA gene. Although these mutations are mutually exclusive, their proteins are coexpressed in many GISTs with various modulations of immunostaining depending on which gene is mutated. CD117 expression is currently considered a sensitive (although not entirely specific) marker of KIT activation, but there is no consensus concerning the reliability of PDGFRA antibody. Our database contains 236 molecularly analyzed GISTs, and we here describe the 180 cases that underwent KIT/PDGFRA immunophenotyping. By correlating the immunophenotype with the molecular status of the genes expected to be involved, we observed the coexpression of KIT and PDGFRA in the majority of the mutated c-Kit and wild-type c-Kit/PDGFRA GISTs, whereas the -/+ immunophenotype (0% vs. 48.6%) and PDGFRA dotlike immunostaining (P<0.005) segregated with the PDGFRA-mutated GISTs. Taking either the dotlike decoration (26 cases) or -/+ immunophenotype (5 cases) as hallmarks of PDGFRA mutation, the presence of a PDGFRA mutation was predicted in 31 (83.8%) of the 37 PDGFRA mutated GISTs. Our findings suggest that, when critically applied, the routine use of CD117/PDGFRA immunophenotyping is a useful diagnostic tool (especially in CD117-negative cases) as it correctly predicts the presence of PDGFRA mutations in most cases.

Neural differentiation with the appearance of ganglion-like cells has been reported in untreated primitive neuroectodermal tumor/Ewing sarcoma (PNET/EWS) at peculiar sites, such as the cauda equina, and following treatment. The case is presented here of a 17-year-old girl with a tumor in the iliac bone. An open biopsy was diagnosed as PNET/EWS of the bone. The tumor had the typical morphology of this tumor type and showed diffuse membranous immunoreactivity for CD99, intense immunoreactivity for synaptophysin, and focal immunoreactivity for neuron-specific enolase and S-100 protein. Occasional reactivity for vimentin was evident, while no immunoreactivity for NB84a, Hu, chromogranins A and B, neurofilaments, cytokeratins, and desmin was present. The patient underwent chemotherapy and radiotherapy, followed by right internal hemipelvectomy. The post-treatment residual viable tumor showed a morphologic appearance resembling a neuroblastoma, with immunoreactivity for NB84a, Hu, synaptophysin, and chromogranins A and B, but not for CD99. RT-PCR performed on tumor tissue before and after therapy showed the presence of the EWS-FLI1 fusion transcript, type I in both samples. This case of PNET/EWS is unique in the sense of showing the typical fusion transcript associated with this tumor both in the morphologically typical pretherapy tumor and in the sample from the post-therapy specimen showing neuroblastoma-like features.

We reclassified 720 nonmedullary invasive thyroid carcinomas diagnosed and treated between 1975 and 1993. Twenty-seven cases met the criteria of insular carcinoma and 29 cases those of widely invasive follicular carcinoma. Comparison of these histotypes with respect to pathologic stage and overall, relative, and visceral metastasis-free survival showed a significant association between histotype and pT and pN categories. In particular, pT4 (p < 0.001) and pN1 (p < 0.001) categories were more frequent in the insular carcinoma histotype. By contrast, no significant differences in overall, relative, or visceral metastasis-free survival were observed between insular carcinoma and widely invasive follicular carcinoma. Molecular analysis by polymerase chain reaction-single-strand conformation polymorphism demonstrated RAS gene family point mutations in five of eight cases analyzed in each of the two histotypes, with a high proportion of CAA-->AAA transversion at codon 61 of the N-RAS gene in insular carcinoma. These findings suggest that insular carcinoma represents a de novo entity distinct from widely invasive follicular carcinoma, that widely invasive follicular carcinoma has biologic characteristics more consistent with poorly differentiated than well-differentiated carcinomas, and that both insular carcinoma and widely invasive follicular carcinoma share similar molecular alterations.

The expression of bcl-2 and p53 was investigated by immunocytochemistry in combination with that of conventional structural and differentiation antigens on the archival material of 22 cases of undifferentiated carcinoma (UC) and 19 of poorly differentiated carcinoma (PDC) of the thyroid gland. The restriction of bcl-2 expression to PDC in comparison to UC was 84.2% versus 13.6% of cases, respectively, in contrast to an almost equal percentage of p53 expression in the two histologic types, that is, 52.6% and 54.5% of cases of PDC and UC, respectively. However, the pattern of distribution of p53-immunoreactive cells was definitely different, being restricted to areas showing active infiltrating growth in PDC and involving almost all tumor cells in UC. Furthermore, in the subset of cases of UC showing the residual presence of a differentiated component, a distinctive mutual exclusion of bcl-2 and p53 immunoreactivity was observed in the two components. The results suggest that the evaluation of bcl-2 expression may be usefully applied to the differentiation of PDC from UC, whereas all morphologic findings related to p53 expression are in keeping with a significant role of the deregulation of this gene in the mechanism of dedifferentiation and progression of the disease.

We studied the clinical, histologic, histochemical, and immunocytochemical characteristics of 61 mucinous tumors (38 pure, 23 mixed) retrieved from a consecutive series of 1,689 infiltrating carcinomas of the female breast. The only statistically significant predictors of favorable survival were histologic (pure) type coupled with the absence of axillary lymph node metastases. Other factors, including classification into A and B types according to Capella et al., and neuroendocrine status, as assessed by the presence of argyrophilia, granins, neuron-specific enolase (NSE), and synaptophysin (SYN),-all had no influence on survival. Argyrophilic cells were found in 16 pure mucinous tumors (42%) and in the mucinous component of four mixed tumors (17%). Granin (chromogranin A or B), NSE, and SYN immunoreactivities were demonstrated in all the argyrophilic tumors. We also found NSE- and SYN-immunoreactive cells in 31 of 41 and 16 of 41 nonargyrophilic (granin-unreactive) mucinous tumors, which supports the view that mucinous carcinomas of the breast as a whole are neuroendocrine-programmed tumors.

Ninety-one tumors (5.6%) containing argyrophilic cells were identified in a series of 1,628 consecutive primary breast carcinomas diagnosed between 1968 and 1972 at the Istituto Nazionale Tumori, Milan, Italy. Histological evaluation of these argyrophilic tumors showed the presence, either throughout the whole tumor mass (pure form) or in some areas (mixed form), of distinctive though not pathognomonic cellular features. Immunocytochemistry revealed the presence of chromogranin A or chromogranin B (secretogranin I) immunoreactivity in 86% of these argyrophilic carcinomas and of neuron-specific enolase (NSE) immunoreactivity in all of them. The three neuroendocrine markers were also immunolocalized at the ultrastructural level in the dense-core granules (granins) and the cytoplasmic matrix (NSE). Immunoblotting studies confirmed the chromogranin A and B and NSE immunoreactivities and documented the presence of secretogranin II. We also studied the relation of the histologic, histochemical, and immunocytochemical features to prognosis. There was no significant correlation between argyrophilia and such clinical parameters as age, menopausal status, tumor size, and overall survival; however, the pure form of argyrophilic tumors had a significant association with less frequent lymph node involvement and a low histologic grade.

Argyrophilic tumors were diagnosed in 28 of 134 (20.8%) consecutive male patients who had a carcinoma of the breast removed between 1961 and 1990. Histologically, most argyrophilic tumors showed uniform cellularity and prevalent expansive growth. Ultrastructural observation disclosed the presence of electron-dense cored granules in the cytoplasm of the tumor cells. By immunocytochemistry, 17 of 28 argyrophilic tumors (60.7%) contained chromogranin B (secretogranin I)-immunoreactive cells, whereas chromogranin A was present in four of these 17 tumors only (14.2%). Immunoblotting studies showed chromogranin B immunoreactivity similar to that found in normal neuroendocrine cells. Despite these findings, which would argue for a distinct morphologic and immunochemical entity, no statistically significant differences between argyrophilic and common male breast carcinomas were found when a number of clinicopathologic features and relapse-free survival were considered.

Of 21 consecutive cases of early vulvar neoplasia studied at the Istituto Nazionale Tumori of Milan, 62% appeared to be related to papillomavirus infection. This conclusion is the result of the present study by in situ hybridization with DNA probes of human papillomavirus (HPV) 6/11, 16, and 18 and of previous ultrastructural and immunohistochemical investigations. The proportion of cases associated with HPV was 78.5% for those (11/14) with histologic evidence of viral infection and 33% for those without (2/6). HPV 16 was detected in all cases that were positive by in situ hybridization except for one, which showed HPV 6/11 DNA. In one case there was a mixed triple infection for HPV 6/11, 16, and 18. The patient who was positive for HPV 6/11 had a giant condyloma associated with an inguinal lymph node containing a metastatic well-differentiated squamous cell carcinoma. Three cases were positive for papillomavirus internal capsid species-nonspecific antigen (PV-Ag) (with ultrastructural evidence of virions in one of them) and were negative for HPV-DNA hybridization. They appeared to be infected with a type of HPV not identified by the available probes. Three cases, and two sites of two other cases with double infection, were HPV-DNA-positive and PV-Ag-negative. They illustrate the limitation of immunohistochemical investigation in cases with high-grade intraepithelial neoplasia. Six cases of verrucous carcinoma of the vulva were negative for HPV DNA by in situ hybridization.

Of 21 patients with predominantly intraepithelial carcinoma of the vulva, 14 had coexisting papilloma virus (PV)-related cytopathic changes in the neoplastic and non-neoplastic epithelial cells. A PV species-nonspecific internal capsid antigen (PV-Ag) was detected in 64% of the cases in a variable number of nuclei by avidin-biotin complex-immunoperoxidase tests. Intranuclear viral particles were identified in 44% of specimens by electron microscopy. The main clinicopathologic features were the gross appearance of multiple papillary growths or, less often, of giant condyloma, the young age of the patients (75% of whom were less than 40 years old), the association in 57% of the cases with simultaneous intraepithelial neoplasia of the cervix or perineal skin, and an incidence of recurrences in 28%. PV infection of the genital area recurred in 14% of the cases. Nodal metastases of squamous cell carcinoma were observed in two cases. The histopathologic features and the main characteristics in terms of natural history of this PV-associated neoplasia are very similar to so-called bowenoid carcinoma and different from those of verrucous carcinoma of the vulva, six cases of which were investigated for comparison. In the latter, the search for PV-Ag was consistently negative, the patients were much older, and metastatic nodal involvement was absent.

Merkel cell carcinoma was diagnosed in 10 patients (eight females and two males) with a mean age of 66 years and a range of 44-84. The most common sites of the primary tumor were the skin of the limbs, girdles, and head. Sixty percent of the cases had recurrences and 50% regional nodal metastases that appeared within 1 year. Of the patients treated variably with surgery, chemotherapy, and radiotherapy and followed for a mean period of 28 months, two were alive and free of disease, two were alive with disease after 3 and 6 years, and two have died of metastatic disease to the lungs and liver. The primary lesions showed quite distinctive clinical and gross features in terms of size, shape, and color. Histologically, the growth was usually diffuse and occasionally trabecular or pseudoglandular; infiltration was predominantly in the papillary and reticular dermis. The uniform, poorly cohesive cells contained argyrophilic granules in the cytoplasm and round to oval nuclei with frequently indented membranes. The mitotic index was high. Ultrastructurally, in two cases, two cell types were identified that probably represented the neoplastic counterpart of normal Merkel cells in different stages of maturation. Both cell types contained cytoplasmic neurosecretory granules and intermediate filaments, even though their cytoplasms were differently shaped.