Investigating the CVD Synthesis of Graphene on Ge(100): toward Layer-by-Layer Growth.

Germanium is emerging as the substrate of choice for the growth of graphene in CMOS-compatible processes. For future application in next generation devices the accurate control over the properties of high-quality graphene synthesized on Ge surfaces, such as number of layers and domain size, is of paramount importance. Here we investigate the role of the process gas flows on the CVD growth of graphene on Ge(100). The quality and morphology of the deposited material is assessed by using µ-Raman spectroscopy, X-ray photoemission spectroscopy, scanning electron microscopy, and atomic force microscopy. We find that by simply varying the carbon precursor flow different growth regimes yielding to graphene nanoribbons, graphene monolayer, and graphene multilayer are established. We identify the growth conditions yielding to a layer-by-layer growth regime and report on the achievement of homogeneous monolayer graphene with an average intensity ratio of 2D and G bands in the Raman map larger than 3.

Nanowire-based field effect transistors for terahertz detection and imaging systems.

The development of self-assembled nanostructure technologies has recently opened the way towards a wide class of semiconductor integrated devices, with progressively optimized performances and the potential for a widespread range of electronic and photonic applications. Here we report on the development of field effect transistors (FETs) based on semiconductor nanowires (NWs) as highly-sensitive room-temperature plasma-wave broadband terahertz (THz) detectors. The electromagnetic radiation at 0.3 THz is funneled onto a broadband bow-tie antenna, whose lobes are connected to the source and gate FET electrodes. The oscillating electric field experienced by the channel electrons, combined with the charge density modulation by the gate electrode, results in a source-drain signal rectification, which can be read as a DC signal output. We investigated the influence of Se-doping concentration of InAs NWs on the detection performances, reaching responsivity values higher than 100 V W⁻¹, with noise-equivalent-power of ∼10⁻9 W Hz(⁻½). Transmission imaging experiments at 0.3 THz show the good reliability and sensitivity of the devices in a real practical application.

Cathepsin-K immunoreactivity distinguishes MiTF/TFE family renal translocation carcinomas from other renal carcinomas.

The microphthalmia transcription factor/transcription factor E (TFE)-family translocation renal cell carcinomas bear specific translocations that result in overexpression of TFE3 or TFEB. TFE3 fusion gene product overexpression occurs as consequence of different translocations involving chromosome Xp11.2, whereas TFEB overexpression is the result of the specific translocation t(6;11)(p21;q12), which fuses the Alpha gene to TFEB. Both TFE3 and TFEB are closely related members of the microphthalmia transcription factor/TFE-family, which also includes TFEC and microphthalmia transcription factor. These transcription factors have overlapping transcriptional targets. Overexpression of microphthalmia transcription factor has been shown to mediate the expression of cathepsin-K in osteoclasts. We hypothesize that the overexpression of the related TFE3 fusion proteins and TFEB in translocation renal cell carcinomas may have the same effect. We studied cathepsin-K in 17 cytogenetically confirmed microphthalmia transcription factor/TFE-family translocation renal cell carcinomas. Seven cases showed a t(6;11)(p21;q12), ten cases showed translocations involving Xp11.2; five cases t(X;1)(p11;q21) resulting in a PRCC-TFE3 gene fusion; three cases t(X;1)(p11;p34) resulting in a PSF-TFE3 gene fusion, one t(X;17)(p11;q25) resulting in an ASPL-TFE3 gene fusion, and one t(X;3)(p11;q23) with an unknown TFE3 gene fusion. As control we analyzed cathepsin-K in 210 clear cell, 40 papillary, 25 chromophobe renal cell carcinomas and 30 oncocytomas. All seven TFEB translocation renal cell carcinomas were labeled for cathepsin-K. Among the cytogenetically confirmed TFE3 translocation renal cell carcinomas, 6 out of 10 were positive. None of the other renal neoplasms expressed cathepsin-K. We conclude the following: (1) cathepsin-K is consistently and strongly expressed in TFEB translocation renal cell carcinomas and in 6 of 10 TFE3 translocation renal cell carcinomas. (2) Cathepsin-K immunolabeling in both TFE3 and TFEB translocation renal cell carcinomas distinguishes these neoplasms from the more common adult renal cell carcinomas, and may be a specific marker of these neoplasms. (3) These results further support the concept that the overexpression of TFE3 or TFEB in these neoplasms activates the expression of genes normally regulated by microphthalmia transcription factor in other cell types.

Parvalbumin is constantly expressed in chromophobe renal carcinoma.

Chromophobe renal carcinoma is composed of neoplastic cell showing several features similar to those found in the intercalated cells of the collecting ducts. Because the distal nephron expresses calcium-binding proteins playing a role in calcium homeostasis, we reasoned that these proteins could be expressed by chromophobe carcinoma and therefore represent a diagnostic marker. We studied the immunohistochemical expression of different calcium-binding proteins (parvalbumin, calbindin-D28K, and calretinin) in 140 renal tumors, including 75 conventional (clear cell) carcinomas, 32 chromophobe carcinomas, 17 papillary renal cell carcinomas, and 16 oncocytomas. Parvalbumin was strongly positive in all primary chromophobe carcinomas and in one pancreatic metastasis; it was positive in 11 of 16 oncocytomas and absent in conventional (clear cell) and papillary renal cell carcinomas, either primary or metastatic. Calbindin-D28K and calretinin were negative in all tumors, with the exception of two chromophobe carcinomas, four oncocytomas, and two papillary renal cell carcinomas showing inconspicuous calretinin expression. Our data demonstrate that parvalbumin may be a suitable marker for distinguishing primary and metastatic chromophobe carcinoma from conventional (clear cell) and papillary renal cell carcinoma. Moreover, they suggest a relationship between chromophobe renal carcinoma and renal oncocytoma and indicate that chromophobe carcinoma exhibits differentiation toward the collecting-duct phenotype.

Multiple radiculopathy of the lower limbs in a cancer patient with meningeal carcinomatosis.

Meningeal carcinomatosis occurs in 1%-5% of patients with breast cancer. Early diagnosis and aggressive treatment of neurologic involvement are important factors of prognosis. We report a case of a 52-year-old woman who was affected by bilateral breast carcinoma treated with surgery and chemotherapy. Six years after she had become asymptomatic, X-rays showed lumbar spine metastases which were treated with radiotherapy. After 1 year she began to suffer from lower limb paresthesias, unsteadiness and unstable gait. Clinical examination showed lower limb sensory ataxia with lack of knee and ankle reflexes, and hypopallesthesia from the iliac spine to the foot. Spinal magnetic resonance imaging (MRI) with contrast agent revealed no medullar compression. Electromyography disclosed bilateral involvement of L4-L5-S1 roots and corresponding paraspinal muscles. Sensory and motor conductions were normal. Cerebrospinal fluid (CSF) examination showed the presence of neoplastic cells, confirming the diagnosis of meningeal carcinomatosis. Our patient underwent 9 cycles of intrathecal methotrexate therapy (25 mg/cycle) with improvement of ataxia and relief of paresthesias. One year later, CSF examination is still negative. We point out the importance of electrodiagnostic studies and CSF examination in the early documentation of root involvement in cancer patients, when computed tomography, MRI and myelography are normal. Early diagnosis may lead to effective therapy which prolongs survival.

Renal angiomyolipoma with epithelioid sarcomatous transformation and metastases: demonstration of the same genetic defects in the primary and metastatic lesions.

Angiomyolipoma (AML) is a benign neoplasm that occurs either sporadically or in patients with tuberous sclerosis complex (TSC) and shows frequent allelic losses at chromosome arm 16p. It has been suggested recently that the melanogenesis marker-positive perivascular epithelioid cell (PEC) has been found consistently in AML. The authors report a 50-year-old woman without evidence of TSC affected by classic renal AML containing an area composed of atypical epithelioid cells with the same morphoimmunophenotypic characters of PEC. After 7 years from surgical removal of the lesion, the patient developed a local recurrence and successive lung and abdominal metastases that showed morphologic and immunohistochemical features overlapping those of the epithelioid area of the previously removed AML. Genetic analysis showed that the classic AML and its epithelioid area as well as the pulmonary and abdominal metastases shared the same allelic loss on chromosome arm 16p. Based on these findings, the authors view this case as evidence of a malignant transformation of a classic AML with morphologic, immunophenotypic, and genetic demonstration of its clonal origin.

[A rare case of acute scrotum. Thrombophlebitis from ectasia of the left pampiniforme plexus]. / Raro caso di scroto acuto. Tromboflebite su ectasia del plesso pampiniforme destro.

The acutely painful scrotum may be due to testicular torsion, twisted testicular appendages, twisted spermatic cord or epididymitis. Most rarely it occurs as a result of a testicular trauma, orchitis, idiopathic scrotal edema, idiopathic infarction of testis and vaginalis tunica or testicular neoplasm; a spontaneous thrombosis of the spermatic vein vessels is quite unusual. A rare case of thrombosis of a dilated pampiniform plexus which occurred in a 6 year-old child is reported and its clinical presentation, diagnosis and treatment is discussed. The difficulty in making such a diagnosis is stressed since thrombosis of the spermatic vein is quite a rare entity; a conservative approach is suggested as a treatment of choice whenever a definite diagnosis is made, otherwise surgical intervention (ligation of the spermatic vein, if necessary) is required in order to rule out any other urologic emergency.

Carcinomalike monotypic epithelioid angiomyolipoma in patients without evidence of tuberous sclerosis: a clinicopathologic and genetic study.

We report the clinicopathologic, immunohistochemical, ultrastructural, and genetic features of an unusual renal tumor composed of large, atypical, densely packed, clear/eosinophilic epithelioid cells. Three patients, two men and one woman (ages 31, 36, and 60 years of age, respectively), had abdominal pain. Morphologically, all cases showed aggressive features (largeness, atypical cells, sarcomatoid features, necrosis, and, in one case, invasion of the renal vein). Despite the marked morphologic resemblance of these tumors to high-grade sarcomatoid renal cell carcinoma, their phenotype (HMB45+, CD68+/-, actin+/-, and vimentin and keratin negative) is in contrast to that observed in epithelial tumors and parallels the phenotypic profile of angiomyolipoma. Ultrastructural analysis showed the presence of glycogen, mitochondria, and prominent electron-dense, membrane-bound granules in the neoplastic cells, and the absence of melanosomes or premelanosomes. Genetic study, performed using polymerase chain reaction from paraffin sections, showed a loss of heterozygosity at the TSC2-containing region on 16p in one case, and on 3p in two cases, showing that multiple genetic alterations are taking place in these tumors. Follow-up has shown local recurrence in one case after 6 years, and the patient died 1 year later of cardiorespiratory failure. The other two patients are well after 26 and 10 months. All three patients were evaluated for signs of tuberous sclerosis, and findings were negative. We suggest that these tumors should be considered close relatives of the angiomyolipoma variants, composed purely of perivascular epithelioid cells. More cases and longer follow-up durations are needed to fully evaluate its prognostic implication.

Apparent renal cell carcinomas in tuberous sclerosis are heterogeneous: the identification of malignant epithelioid angiomyolipoma.

Renal epithelial tumors (carcinoma and oncocytoma) have been reported with higher a frequency than expected in patients with the tuberous sclerosis complex. However, the recent identification of a monotypic, epithelioid variant of angiomyolipoma, closely simulating renal cell carcinoma, has cast doubt on the real frequency of carcinoma. Immunohistochemical analysis with a panel of antibodies, including melanogenesis marker HMB45, can discriminate between carcinoma and carcinoma-like angiomyolipoma. We studied five tumors previously reported as carcinoma and found that only one of them showed an immunohistochemical phenotype indicative of an epithelial tumor (Ker+, HMB45-). Three tumors exhibited a phenotype compatible with the monotypic epithelioid variant of angiomyolipoma (HMB45+, Ker-), and two of the three patients died of metastatic disease. The last patient had unusual clinical features, and the tumor was positive both for HMB45 and keratin. It is concluded that (1) renal cell carcinoma is less common in tuberous sclerosis complex than previously believed, (2) some cases called renal cell carcinoma probably represent a monotypic, epithelioid variant of angiomyolipoma, and (3) epithelioid angiomyolipoma is a potentially malignant tumor with invasion and metastases. These findings indicate that all reported renal carcinomas in tuberous sclerosis complex, therefore, must be reevaluated.

Congenital cystic mesoblastic nephroma.

Congenital mesoblastic nephroma is a relatively rare infantile renal tumor. It comprises 3-6% of renal masses in childhood and 50% during the neonatal period. Most mesoblastic nephroma occur in the newborn period, with 80% of the cases being reported within the first month of life. Macroscopically the tumor is composed of a solid mass of different sizes tending to invade the surrounding structures and renal parenchyma. The authors report a case of cystic mesoblastic nephroma of the cellular subtype, with diffuse areas of hemorrhage and necrosis. The tumor was treated by surgical excision with radical nephrectomy and the child is doing well 4 years after the operation.

Anti-melanoma monoclonal antibody HMB-45 on enhanced chemiluminescence-western blotting recognizes a 30-35 kDa melanosome-associated sialated glycoprotein.

HMB-45 is an anti-melanoma monoclonal antibody widely used in diagnostic pathology owing to its great specificity in identifying poorly differentiated melanomas. In this study, by a series of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) immunoblots with the enhanced chemiluminescent (ECL) detection method on the HU-214 melanoma cell line, we identified the antigen of HMB-45 in a protein or proteins of 30-35 kDa. Although this result is in discrepancy with the previous literature which identified the antigen as a protein of 7 or 10 kDa, a family of proteins of 25-70 kDa of as a protein of 100 kDa (gp100), the present data indicate that the antigen signal we found might be specific. Furthermore, immunoblots on neuraminidase-treated cell lysates show, in agreement with already published data, that the antigen might be a sialated glycoprotein with the sialic acid involved in the epitope. Immunoblots on partially purified melanosomes confirmed the presence of the antigen in these organelles.

Clear cell "sugar" tumor of the pancreas. A novel member of the family of lesions characterized by the presence of perivascular epithelioid cells.

We report at unique, previously unreported pancreatic tumor occurring in a 60-year-old woman who was preoperative diagnosed on cytoaspiration as having clear cell carcinoma. The resected tumor consisted of a population of large epithelioid cells with clear or eosinophilic, granular cytoplasm, rich in glycogen, with nuclear pleomorphism and no mitotic activity. In spite of the epithelioid appearance, the tumor cells were negative for epithelial (CAM 5.2, KL1, AE1-AE3), endocrine (neuron-specific enolase [NSE], chromogranin A), and acinar (lipase, amylase) markers and positive for actin and melanogenesis-related marker HMB 45. Ultrastructurally, the neoplastic cells showed membrane-bound granules; no evidence of either epithelial or melanocytic differentiation was present. These morphophenotypic features have never been reported in a pancreatic tumor and overlap those of clear cell "sugar" tumor of the lung. The same morphophenotypic features are observed in a family of lesions characterized by the presence of the perivascular epithelioid cell that also includes lymphangiomyomatosis and angiomyolipoma. The present case may be considered a novel member of this family of lesions. We propose this new entity be named clear cell "sugar" tumor of the pancreas.

Carcinoma-like signet-ring cells in gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

We noticed the presence of epithelial signet-ring cells (SRCs) in a proportion of primary gastric B-cell lymphomas, and in some endoscopic biopsies we found it difficult to decide whether they represented an associated carcinoma. To evaluate the frequency and nature of this phenomenon, we reviewed 108 stomachs resected for primary lymphoma, including 70 mucosa-associated lymphoid tissue (MALT) and 38 non-MALT lymphomas. We found SRCs, either isolated or grouped in clusters, in 26 of 70 MALT lymphomas. The SRCs were always localized in the superficial portion of the lamina propria and associated exclusively with lymphomatous areas. Isolated and scarce SRCs were also found in four of 22 cases of polyclonal atypical lymphoid hyperplasia. Our data suggests that SRCs occurring in gastric MALT lymphomas represent a particular type of LEL in which the foveolar cells disaggregated by the lymphomatous infiltration acquire a globoid, signet-ring appearance. These "foveolar" LELs are found in 37% of MALT lymphomas and are usually associated with the more classic and constant "neck" LELs, which are localized between the foveolae and mucopeptic glands. An awareness of the existence of the foveolar LEL may help avoid overdiagnosis of SRC carcinoma on gastric endoscopic biopsies.

Clear cell ("sugar") tumor of the lung is a lesion strictly related to angiomyolipoma--the concept of a family of lesions characterized by the presence of the perivascular epithelioid cells (PEC).

We report a comparative study of 3 clear cell tumors of the lung (CCTL) and 3 angiomyolipomas (AML) of the kidney. Morphological analysis shows that the cells of CCTL are identical to the perivascular epithelioid component of AML. Phenotypically they both consistently expressed melanoma-associated antigens recognized by Moabs HMB45 and HMSA-1, while they were negative for HMSA-5. A minority of cells also expressed S-100 protein, vimentin and actin. In addition, one case of CCTL showed mature adipose tissue entrapped in the proliferation, thus suggesting an intermediate form between CCTL and AML. Based on morphological and phenotypical similarities, it is suggested that CCTL and AML belong to the same family of lesions, characterized by the presence of a peculiar muscle cell, expressing different melanoma-associated antigens.

Preoperative diagnosis of renal angiomyolipoma: fine needle aspiration cytology and immunocytochemical characterization.

A preoperative diagnosis of renal angiomyolipoma (AML) is of great importance for a correct management of these patients with this tumor. In fact when the lesion is small and asymptomatic a conservative approach may be considered. We have evaluated the radiographic and fine needle aspiration cytology (FNAB) findings in 8 cases of AML. In 3 cases both radiology and cytology were suggestive of carcinoma and thus the patients underwent surgery. In one case both techniques suggested AML but surgery was performed because the lesion was large and symptomatic. In 4 cases where both radiology and cytology suggested AML no surgery was performed. Follow-up data are consistent with the benign nature of the lesions. The immunocytochemical analysis of the FNAB with a panel of antibodies including keratin, vimentin, actin and HMB-45 was indicative of AML in 7 of 8 cases, including 2 of the 3 cases misdiagnosed as carcinomas. The presence of HMB-45-positive perivascular epithelioid cells in the FNABs was the most significant finding. It is concluded that immunocytochemical analysis of FNAB with this monoclonal antibody panel can increase the accuracy of preoperative diagnosis of AML, and allow consideration of a conservative approach in selected cases.

[Pulmonary carcinoid tumors]. / I tumori carcinoidi polmonari.

27 patients suffering from carcinoid of the lung (18 females and 9 males, middle age 52 years, range 26-68) underwent surgery in our department. The neoplasms were located at the pulmonary hilum in 21 cases. The diagnosis was occasional in 6 cases, cough (51.8%) and recurrent bronchitis (37%) were the most frequent symptoms. No instances of carcinoid syndrome were detected. Preoperative staging ruled out pathologic mediastinal lymph nodes or hematogenous metastases. 26 patients underwent complete excision of the neoplasm (11 lobectomies, 9 pneumonectomies, 4 bilobectomies, 1 segmental resection, 1 bronchial wedge resection). Histologically, 4 cases were categorized as atypical carcinoids. Two patients died within 1 year, one suffering from atypical carcinoid because of disease progression, and an other one (suffering from atypical carcinoid) who underwent only at exploratory thoracotomy followed by chemotherapy. A patient suffering from typical carcinoid died within 1.5 years because of gallbladder carcinoma. From our experience and from the literature review it appears that carcinoids has to be considered as malignant neoplasms and treated according to.

Transbronchial biopsy in lymphangiomyomatosis of the lung. HMB45 for diagnosis.

We have investigated the presence of smooth muscle cells with immunoreactivity for melanoma-related marker HMB45 in pulmonary lymphangiomyomatosis (PLAM). Of 75 lung specimens, including a variety of lesions (obtained with both transbronchial and open lung biopsies), only PLAM (six specimens from three patients) showed the presence of HMB45-positive cells. In addition, 20 specimens of normal lung were unreactive with this monoclonal antibody. It is concluded that the smooth muscle cells of PLAM regularly exhibit a peculiar phenotype, characterized by HMB45 immunoreactivity, distinct from other smooth muscle proliferations; and the histological diagnosis of PLAM can be made when only a transbronchial biopsy is available.