Andrea Tironi

Is the anteroposterior and transverse diameter ratio of nonpalpable thyroid nodules a sonographic criteria for recommending fine‐needle aspiration cytology?

Background  As a consequence of the increasing application of ultrasound (US) technology, the detection of asymptomatic nonpalpable thyroid nodules has generally increased. The aim of our study was to assess if the anteroposterior and transverse diameter ratio of nonpalpable thyroid nodules (A/T) ≥ 1 could be a sonographic criterion for recommending fine‐needle aspiration cytology (FNAC).

BAP1 (BRCA1-associated protein 1) is a highly specific marker for differentiating mesothelioma from reactive mesothelial proliferations

The distinction between malignant mesothelioma and reactive mesothelial proliferation can be challenging both on histology and cytology. Recently, variants of the BRCA1-associated protein 1 (BAP1) gene resulting in nuclear protein loss were reported in hereditary and sporadic mesothelioma. Using immunohistochemistry, we evaluated the utility of BAP1 expression in the differential diagnosis between mesothelioma and other mesothelial proliferations on a large series of biopsies that included 212 mesotheliomas, 12 benign mesothelial tumors, and 42 reactive mesothelial proliferations. BAP1 stain was also performed in 70 cytological samples (45 mesotheliomas and 25 reactive mesothelial proliferations). BAP1 was expressed in all benign mesothelial tumors, whereas 139/212 (66%) mesotheliomas were BAP1 negative, especially in epithelioid/biphasic compared with sarcomatoid/desmoplastic subtypes (69% vs 15%). BAP1 loss was homogeneous in neoplastic cells except for two epithelioid mesotheliomas showing tumor heterogeneity. By fluorescence in situ hybridization, BAP1 protein loss was paralleled by homozygous deletion of the BAP1 locus in the vast majority of BAP1-negative tumors (31/41, 76%), whereas 9/10 BAP1-positive mesotheliomas were normal. In biopsies interpreted as reactive mesothelial proliferation BAP1 loss was 100% predictive of malignancy, as all 6 cases subsequently developed BAP1-negative mesothelioma, whereas only 3/36 (8%) BAP1-positive cases progressed to mesothelioma. On cytology/cell blocks, benign mesothelial cells were invariably positive for BAP1, whereas 64% of mesotheliomas showed loss of protein; all 6 cases showing BAP1 negativity were associated with histological diagnosis of BAP1-negative mesothelioma. BAP1 stain also showed utility in the differential of mesothelioma from most common pleural and peritoneal mimickers, such as lung and ovary carcinomas, with specificity and sensitivity of 99/70% and 100/70%, respectively. Our results show that BAP1 protein is frequently lost in mesothelioma, especially of epithelioid/biphasic subtype and is commonly associated with homozygous BAP1 deletion. BAP1 immunostain represents an excellent biomarker with an unprecedented specificity (100%) in the distinction between benign and malignant mesothelial proliferations. Finding BAP1 loss in mesothelial cells should prompt to immediately reevaluate the patient; moreover, it might be useful in mapping tumor extent and planning surgical resection.

Linker for Activation of T Cells (LAT), a Novel Immunohistochemical Marker for T Cells, NK Cells, Mast Cells, and Megakaryocytes : Evaluation in Normal and Pathological Conditions

LAT (linker for activation of T cells) is an integral membrane protein of 36-38 kd that plays an important role in T cell activation. Using a rabbit polyclonal antibody generated against the cytosolic portion of LAT, we investigated the immunohistochemical expression of LAT in normal and pathological hematolymphoid tissues. LAT reacts with human T cells in paraffin sections, including decalcified bone marrow trephines. LAT appears early in T cells at the thymocyte stage and before TdT expression in embryos, and is expressed in peripheral lymphoid tissues, without restriction to any T cell subpopulations. In addition to T cells, natural killer (NK) cells (evaluated with flow cytometry), megakaryocytes and mast cells are also LAT-positive, whereas B cells and other myeloid and monocytic derived cells are negative. Tested on a total of 264 paraffin-embedded tissue biopsies, LAT reacted with the great majority (96.8%) of T/NK-cell neoplasms, covering the full range of T cell maturation. Although antibodies to both LAT and CD3 had a similarly high sensitivity in the staining of T/NK-cell lymphomas, when used in conjunction, they successfully identified a higher number of cases (98.4%). Atypical megakaryocytes from different hematological disorders, as well as mast cells in mastocytosis were also LAT-positive, but all neoplasms of B cell origin, Hodgkins lymphomas, and several nonlymphoid malignancies were negative. These data indicate that the anti-LAT antibody may be of value to diagnostic histopathologists for the identification of T cell neoplasms.

Oncogene-induced senescence distinguishes indolent from aggressive forms of pulmonary and non-pulmonary Langerhans cell histiocytosis

Abstract The clonal/neoplastic nature of Langerhans cell histiocytosis (LCH) has recently been demonstrated by a high prevalence of BRAF mutations, including pulmonary LCH (PLCH). We hypothesized that BRAF-induced senescence, as demonstrated in nevi and melanoma, is involved in the pathogenesis of LCH and PLCH. In a series of pulmonary (19 cases) and non-pulmonary LCH (19 cases), including five aggressive cases, we investigated occurrence of the BRAF V600E mutation by molecular analysis and/or immunohistochemistry using a validated antibody (VE1). The expression of cell-senescence markers p16INK4a and p21CIP1/WAF1 was also immunohistochemically investigated. We demonstrated that 6/19 cases of LCH and 12/19 cases of PLCH were VE1 positive, matching with molecular analysis, and in all cases both p16INK4a and p21CIP1/WAF1 were expressed, irrespective of BRAF mutation status. Interestingly, all the aggressive cases did not express p16INK4a, thus suggesting that loss of senescence control could be related to clinical aggressiveness of LCH, as in melanoma.

Fine needle cytology of complex thyroid nodules

OBJECTIVE To evaluate whether a preliminary aspiration (ASP) of the cystic component and/or using spinal needles in complex thyroid nodules (CTN) could improve the adequacy of cytological sampling. METHODS Between January 2004 and December 2006, 386 consecutive patients with CTN were enrolled in this prospective investigation. Ultrasound (US) fine needle aspiration cytology (FNAC) of the solid component of the nodule (one nodule per patient) was performed using two different 25 gauge needles, with (Yale Spinal, YS) or without (Neolus, NS) a stylet, in alternate sequence on consecutive patients. In addition, a subgroup of patients presenting larger cystic component (approximately 50%) was submitted to total aspiration of the cystic component (ASP+) or not submitted (ASP-) before US-FNAC, in alternate sequence within each needle type group. All the samplings were performed by a single endocrinologist. RESULTS Adequate specimens were observed in 163 (84.5%) and 183 (94.8%) nodules investigated by NS and YS respectively. Sampling with the stylet needle was associated with an overall significant reduction of non-diagnostic specimens (15.5% vs 5.2% by NS and YS respectively, P < 0.001). The favourable result obtained with YS was independent from preliminary aspiration of the cystic component (ASP+: 14.8% vs 5.7% by NS and YS; ASP-: 16.2% vs 4.8%, not significant). A logistic regression analysis, taking into account nodule size and presence of intranodal vascularity at eco-colour evaluation of the solid component, confirmed that needle type was the only significant predictor of successful sampling (odds ratio 3.6 (95% confidence interval 1.7-7.6), P < 0.001). CONCLUSIONS Our data show that adopting stylet needles to perform FNAC in CTN may significantly improve the percentage of adequate sampling. On the other hand, preliminary aspiration of CTN with large cystic component does not add any advantage.

Chromosome 9 instability and alterations of p16 gene in squamous cell carcinoma of the lung and in adjacent normal bronchi: FISH and immunohistochemical study

Aims: p16, a tumour suppressor gene located at 9p21 chromosome and involved in cell cycle regulation, is often inactivated in lung carcinoma. Inactivation is also supported by the loss of p16 protein, a strong inhibitor of cyclin‐dependent kinase (CDK) 4 and 6. The aim of this study was to examine alterations of p16 both in pulmonary squamous cell carcinoma (SCC) and in morphological normal bronchi contiguous with neoplasia.

Cost-effectiveness of fine-needle-aspiration cytology of thyroid nodules with intranodular vascular pattern using two different needle types.

AbstractObjective: To compare the cytological findings of hypoechoic thyroid nodules with intranodular vascular pattern (pattern II) obtained by two different needles (Neolus 25 gauge, Chemil, Wenzhou, China vs Yale Spinal 25 gauge, Becton Dickinson, Madrid, Spain) in euthyroid patients and to evaluate their cost-effectiveness. Methods: From January 2001 to December 2003, 480 euthyroid patients with a hypoechoic thyroid nodule pattern II were referred for US-FNAC. The nodules were alternatively evaluated by Neolus or by Yale Spinal with the stylet (YS+) or without the stylet (YS−), in order to evaluate if the cytological results could be due to the presence of the stylet or to the different length of the two needles. For each nodule two passes were performed and the material was obtained by capillary action. Material was smeared on slides, fixed, and stained by Papanicolaou techniques. Cytological specimens were evaluated in blind by the same experienced cytopathologist. Results: Inadequate cytological specimens because of blood contamination were present in 30 (18.7%) samples by Neolus needle and in 22 (13.8%) by YS− compared to only 5 (3.1%) by YS+. In 6 (20%) cases of the 30 repeated US-FNAC by Neolus and in 4 (18%) of the 22 US-FNAC by YS−, material remained inadequate for diagnosis because of blood contamination. All the five repeated samples obtained by YS+ became adequate for diagnosis and resulted benign nodules. Direct costs of US-FNAC procedure are currently Э 72.30 including cytological examination. The cost of Neolus and Yale needles is Э 0.19 and Э 3.0, respectively. The estimated total cost to obtain a cytological diagnosis by a Neolus needle (160 + 30 repeated US-FNAC) was Э 13809.2 vs Э 12919.5 by Yale Spinal needle (160 + 5 repeated US-FNAC). Conclusion: This study demonstrates that the use of Yale Spinal needles greatly reduces inadequate cytological specimens, and therefore limits both direct and indirect costs.

Spinal needle improves diagnostic cytological specimens of thyroid nodules.

Ultrasound fine needle aspiration cytology (US-FNAC) represents the most effective test available to distinguish between benign and malignant thyroid nodules, with an accuracy approaching 95%. The major limit of this procedure it is the rate of inadequate specimens which is reported to be from 10% to 31%. Also because cost considerations have always been important and have recently become even more relevant for clinical guidelines in many countries, it is desirable to limit the number of inadequate samples. Recently, we have shown that the use of stylet needles greatly reduces inadequate cytological specimens in thyroid nodules with an intranodular vascular pattern. With the aim to improve our previous results, we have extended our procedure to all thyroid solid nodules. Between February 2004 and March 2006, 312 consecutive patients with thyroid nodule without intranodular vascular pattern at color-Doppler evaluation were enrolled in this rospective study. US-FNAC was performed by two different 25 gauge needles (Neolus [Ns] and Yale Spinal [YS]), and the two procedures were performed in alternate sequence on consecutive patients. Adequate specimens were observed in 145 (92.9%) and 153 (98%) nodules respectively investigated by Ns and in YS (p<0.005). The total cost to obtain a cytological diagnosis by Ns was of € 12210.2 (156+12 repeated US-FNAC), whereas it was of € 12449.7 by YS (156+3 repeated US-FNAC). Our data suggest that spinal needles are associated with a low proportion of inadequate FNAC, without increase of total direct cost, considering also the number of FNAC repetitions needed; therefore, their routine use could be taken into account.

Perivascular epithelioid cell tumor located retroperitoneally with pulmonary lymphangioleiomyomatosis: report of a case.

Perivascular epithelioid cell neoplasms, also known as “PEComas”, are unusual mesenchymal tumors, exhibiting perivascular epithelioid cell differentiation and characterized by a mixed myogenic and melanocytic phenotype. “PEComas not otherwise specified” (PEComas-NOS) are especially rare; consequently, there are no published large series, but only case reports. These tumors are rarely located retroperitoneally, with only about 15 such cases reported. We report a case of pulmonary diffuse lymphangioleiomyomatosis with large retroperitoneal PEComa-NOS in a 66-year-old woman. Treatment consisted only of tumor resection, without additional adjuvant therapy. We emphasize the importance of correct immunohistochemistry diagnosis, initiation of recommended treatment, and surveillance of this unique family of tumors.

Pulmonary hamartoma mimicking a mediastinal cyst-like lesion in a heavy smoker

Pulmonary hamartoma (PH) is the most common benign tumor of the lung, typically presenting as a peripheral solitary nodule with round shape and smooth margins. The main computed tomography (CT) features that allow a confident diagnosis of PH are intranodular fat and popcorn-like calcifications. However, the presence of these features within PHs is variable. Thus, a reliable diagnosis of PH cannot be formulated in approximately 30% of cases. Furthermore, PHs may occasionally show atypical CT features. The present article reports the case of a centrally located PH with an extremely rare and previously unreported CT presentation consisting of fluid attenuation, rim enhancement and thick enhancing septa that mimicked a mediastinal cyst-like lesion.