Peripheral nerve sheath myxoma. Clinicopathological and immunohistochemical study of a morphologically distinctive myxoid peripheral nerve sheath tumor in the forelimb of a cat

Peripheral nerve sheath tumors (PNST) are a class of nervous system tumors which arise in both schwann cells and perineural fibroblasts. Benign and malignant PNSTs are reported to occur in all domestic animals. In cats they represent 3% of all cutaneous and subcutaneous neoplasms. Only in dogs mixoid PNST has been observed generally localized in the fingers. In humans, PNSTs are rare neoplasms, and nerve sheath myxomas are a distinct neoplasia most commonly found in limb extremities

Osservazioni istochimiche e immunoistochimiche sull'ipofisi anteriore di un cane affetto da malattia di Cushing

Gli adenomi del lobo anteriore dell'ipofisi sono neoplasie benigne piuttosto frequenti. Essi mostrano aspetto circoscritto e accrescimento non invasivo nei confronti dei tessuti circostanti. Il tumore a cellule secernenti ACTH, che colpisce le cellule cromofobe della pars anteriore dell'ipofisi, è uno di questi e viene associato alla sindrome di Cushing, causando evidente ipercortisolemia per stimolazione della corteccia surrenale. Un cane meticcio, femmina, di 7 anni, in terapia per sospetta Sindrome di Cushing e pervenuto a morte, è stato sottoposto ad accurato esame necroscopico, durante il quale si procedeva tra l'altro a prelevare ghiandole surrenali, polmone, fegato, cute, muscoli e intera ghiandola pituitaria. Su detti organi veniva eseguito l'esame istopatologico per la ricerca delle lesioni tipiche determinate dalla sindrome. Sulla ghiandola pituitaria, aumentata notevolmente di volume, venivano eseguite indagini istopatologiche specifiche, mediante colorazione OFG, per differenziare gli istotipi costituenti la pars anteriore. Tale colorazione ha consentito di riscontrare e identificare tra le cellule pituitarie gli elementi acidofili, basofili e cromofobi; queste ultime cellule, aumentate di numero, erano d'aspetto omogeneo e formavano un nucleo compatto e con scarso stroma al centro della ghiandola. La caratterizzazione cromatica e la differenziazione dai restanti istotipi ha reso possibile identificare la neoplasia come adenoma ipofisario di tipo "diffuso", caratterizzato per l'appunto da cellule disposte a strati, con scarso stroma e debole vascolarizzazione. Per verificare l'ormonoattività  delle cellule neoplastiche si è proceduto all'esame immunoistochimico per la ricerca dell'ACTH. Il risultato di tale indagine ha dato esito positivo, confermando l'intensa attività secernente delle cellule oggetto di studio

Un Infrequente caso di "spindle cell tumor" a localizzazione splenica primaria in un cane: rilievi citologici ed istopatologici, osservazioni istochimiche ed immunoistochimiche

Tutti i tumori fusocellulari derivano verosimilmente da una unica cellula staminale mesenchimale pluripotente. Macroscopicamente e microscopicamente i tumori delle cellule muscolari lisce e i tumori del tessuto connettivo fibroso, si presentano morfologicamente simili. Abbiamo ritenuto interessante riferire su un cane meticcio, maschio, di quattro anni sottoposto ad eutanasia dopo aver mostrato letargia, anoressia e perdita di peso. Alla necroscopia si osservava una voluminosa neoformazione splenica di colore biancastro, dura e di consistenza fibrosa. Il fegato si presentava notevolmente aumentato di volume con numerose neoformazioni di piccole e medie dimensioni. Diversi campioni appartenenti agli organi sopramenzionati, venivano sottoposti ad una prima osservazione citologica. Parte di questi, dopo fissazione in formalina venivano inclusi in paraffina. Sezioni di 3-5 μ erano sottoposte a colorazioni ordinarie e speciali (H. E., tricromica di Mallory Azan e Van Gieson). Si eseguivano prove immunoistochimiche utilizzando il seguente algoritmo anticorpale: anti pan-citocheratine, anti vimentina, anti fattore VIII, anti-αactina L, anti desmina, anti CD 15, anti S-100. La neoplasia, altamente infiltrante, era costituita da ampi fasci intrecciati di cellule allungate fusiformi, fibroblastosimili, a moderato indice mitotico, disposte in maniera ordinata, a spina di pesce. Esse risultavano positive alla vimentina e alla αactina L e negative alla desmina. Dette caratteristiche ci consentivano di formulare diagnosi di fibrosarcoma, neoplasia a infrequente localizzazione splenica primaria, e di identificare come metastasi della stessa, le neoformazioni riscontrare a livello epatico

Histopathological, histochemical and immunoistochemical study on a rare case of granulocytic sarcoma in a dog

Granulocytic sarcoma is a malignant extramedullary solid tumor, composed of granulocytic precursor cells at various levels of differentiation. Three differentiation levels are considered: blastic, immature, and differentiated, and cases with unusual morphology. Nowadays the aid of more and more highly developed techniques allows to differentiate the various histotypes. We report a case of a 5 year-old female Schnautzer dog, died after a serious dyspnoea. During the autopsy the veterinary found several neoplasias in the lungs. It has been found a very large white-greyish mediastinal neoplasia, stuck at the trachea and several more in the parenchyma. Several samples were fixed in formalin, embedded in paraffin and exposed to histochemistry staining (H.E., Giemsa), cytochemistry (Naphthol-AS-D-Chloroacetate), and immunohistochemistry (anti-CD3, -CD79a, -CD45, -MPO, -CD45Ro, -CD34, -CD20, -CD68, -CD15, -CD30, -CD117, -CD235a, -Factor VIII, -elastase and anti-Pan-cytocheratine). Neoplasia, poorly circumscribed, was composed by a large number of neutrophil granulocytes with different degrees of differentiation, including elements of myeloid lineage. Cells were positive to MPO and focal to Naphtol-As-D-Chloroacetate and were negative to all the others antisera, allowing us to exclude lymphomas, small cells carcinomas, and tumors of monocytic and erythroid origin. By these characteristics we could diagnose a rare case of neutrophilic granulocytic sarcoma, of immature type progressing to mature form

Complesso ipertrofia mammaria-fibroadenoma nel gatto: osservazioni anatomo-istopatologiche e immunoistochimiche

Il “complesso ipertrofia mammaria-fibroadenoma” (MH-FC) è una mastopatia caratterizzata da una proliferazione displastico/neoplastica degli acini, dei dotti e dello stroma mammario con rapido e considerevole aumento di volume dell’organo. La patologia, di cui sono stati descritti casi di regressione spontanea (Mendel et al., 1973) non è correlata a fattori di razza ma tende a manifestarsi soprattutto nei soggetti di età inferiore ai 2 anni. I realtà il complesso fibroadenoma- ipertrofia mammaria sembra dipendere dalla stimolazione endogena e/o esogena di tipo progestinico

Vimentin-typing in diagnostic surgical pathology: a comparative study using four antibodies after different fixations

Vimentin-typing was carried out on various normal and neoplastic tissues using four anti-vimentin antibodies in order to evaluate the effect of different fixation treatments on tissue reactivity in comparison to the results obtained on frozen sections. All antisera were reactive on frozen material; on paraffin embedded material staining of tissues depended on the type of fixation method applied (formalin, methacarn or absolute alcohol) and each antibody behaved differently in relation to the fixative used. Only mesenchymal normal structures were revealed on frozen material whilst on paraffin embedded material three of the four antibodies reacted also with non-mesenchymal normal structures (epithelia, central and peripheral nervous system cells). All four antibodies decorated, regardless of treatment, neoplastic cells of mesenchymal and non-mesenchymal derivation, but not germ cells or germ cell tumors. The reactivity of vimentin to its specific antibodies depends on the fixative used: therefore, in routine pathology more than one antiserum should be available for testing. Furthermore, given the variety of non-mesenchymal structures stained by the anti-vimentin antibodies, the differential diagnosis of undifferentiated tumors must not be based on vimentin positivity alone. The expression of vimentin by non-mesenchymal neoplastic cells seems to parallel that of normal tissues during embryogenesis; therefore, this intermediate filament appears to be not only a marker of mesenchymal cells but also of many immature elements

Neuron-specific enolase (gamma enolase, gamma-gamma dimer) expression in Hodgkin's disease and large cell lymphomas

BACKGROUND: The presence of gamma-enolase, gamma gamma dimer, or neuron-specific enolase (NSE) has been demonstrated in miscellaneous tumors, including malignant lymphomas. Up to now these results have been interpreted as non-specific, although NSE can be expressed by normal B and T lymphoid cells at a particular stage of differentiation. The aim of the present study was to investigate the expression of NSE in a large series of malignant lymphomas, including Hodgkin's disease, in relation to morphology and immunophenotype. MATERIALS AND METHODS: Frozen and paraffin embedded sections from 16 cases of Hodgkin's disease (4 lymphocyte predominance, nodular; 4 mixed cellularity; 6 nodular sclerosis; 2 lymphocyte depletion) and 35 cases of non-Hodgkin's lymphomas were investigated in order to evaluate the expression of NSE, its specificity and correlation to immunophenotype or other immunological cell markers. Among the non-Hodgkin's lymphomas, there were 9 Anaplastic Large Cell (CD30+) Lymphomas; 2 Peripheral Large T-Cell Lymphomas; 22 Diffuse Large B-Cell Lymphomas and 2 Primary Mediastinal Large B-Cell Lymphomas. RESULTS: In Hodgkin's disease, NSE showed a diffuse cytoplasmic reaction in CD30+ Reed-Sternberg cells, whereas the "popcorn" (L&H) cells of lymphocyte predominance, nodular variant cases, were always negative. Among the non-Hodgkin's lymphomas, NSE positivity was found only in lymphomas expressing CD30. All the other cases were negative. No relationship was found between NSE and B- or T-immunophenotype. CONCLUSIONS: Our results suggest that a link between NSE and CD30 expression exists in malignant lymphomas. However, at the moment this has not been sufficiently investigated and is subject to speculation

S-100A1 is a reliable marker in distinguishing nephrogenic adenoma from prostatic adenocarcinoma

Nephrogenic adenoma is a benign lesion that may occur at any site of the genitourinary tract, usually in association with previous urothelial injuries. Although its pathogenesis is still debated, recent studies seem to confirm its derivation from renal tubular epithelium, rather than from a metaplastic process of urothelium. In addition to its uncertain origin, there can be diagnostic difficulty in distinguishing nephrogenic adenoma from prostatic adenocarcinoma, particularly with lesions arising in the prostatic urethra. So far, immunohistochemical stains are often needed to make such a distinction, and several markers have been proposed, often with controversial results. S100A1 is a calcium binding protein that has been recently reported to be expressed in renal tubular cells and in a subset of renal cell neoplasms. Alpha-methylacyl-CoA racemase (AMACR), a recently identified prostate cancer marker, has also been found to be expressed in renal tubules and in some renal epithelial neoplasms. In this study, we investigated the expression of S100A1 and AMACR in 18 nephrogenic adenomas and in 100 prostatic adenocarcinomas. A strong and distinct cytoplasmic or nucleocytoplasmic staining of S100A1 was found in 17 out of 18 cases of nephrogenic adenoma (94%), but never in prostatic adenocarcinoma. In contrast, AMACR expression was detected in 14 of 18 nephrogenic adenomas (78%) and in 96 of 100 prostatic adenocarcinomas (96%). We conclude that (1) S100A1 is a specific and sensitive immunohistochemical marker to differentiate nephrogenic adenoma from prostatic adenocarcinoma; (2) AMACR immunostaining does not seem to be a useful marker in distinguishing between these 2 lesions; (3) given that both S100A1 and AMACR have been reported to be expressed in renal tubular cells and in a subset of renal cell neoplasms, our findings confirm the histogenetic relationship between nephrogenic adenoma and renal tubular epithelium

High sensitivity of reverse-hybridization methodology in the detection of KRAS mutations from formalin-fixed paraffin-embedded colorectal cancer samples

Colorectal cancer is ranked the third most common cancer worldwide in terms of incidence and the second in terms of mortality. Recent advances in therapeutic approaches to colorectal cancer have identified a potential role of antiepidermal growth factor receptor (EGFR) targeted therapies as adjuvant treatment in advanced disease. New evidences showed that patients harboring KRAS mutations on codons 12 and 13 are not responsive to anti-EGFR monoclonal antibodies. Therefore, new mutational screening tools have been proposed to select patients who will benefit from anti-EGFR targeted therapy, reducing inappropriate, expensive treatments and unwarranted side effects. We evaluated the performance of a reverse-hybridization-based assay in the identification of the most frequent KRAS mutations on a series of 50 formalin-fixed, paraffin-embedded, advanced colorectal cancer specimens, in comparison with the direct gene sequencing technique. Thirtytwo of the 50 cases (64%) showed KRAS single point mutations by reverse-hybridization technique. In particular, 93.8% of the mutations were reported on codon 12, whereas 6.2% of the mutations were reported on codon 13. Direct gene sequencing showed KRAS mutations on 28 of the 50 cases (56%) with 96.4% of the mutations on codon 12 and 3.6% on codon 13. Concordance between the assays was observed in 92% of the cases. Both reverse hybridization and gene sequencing methods have been shown to be suitable tests in detecting KRAS mutations from formalin-fixed, paraffin-embedded tumor specimens. In our experience, reverse-hybridization technique has been shown to be an effective and more sensitive assay for the identification of the most common KRAS mutations

Evaluation of methylation degree from formalin-fixed paraffin-embedded DNA extract by field-amplified sample injection capillary electrophoresis with UV detection

Alterations in global DNA methylation are implicated in several pathobiological processes. The tissues stored as paraffin blocks represent an important source of DNA for retrospective genetic and epigenetic analysis on a large scale. Therefore, we developed the first capillary electrophoresis method able to measure global methylation in formalin-fixed, paraffin-embedded (FFPE) DNA extracts. A field-amplified sample injection capillary electrophoresis method with UV detection for the separation and quantification of cytosine and 5-methylcytosine released following DNA hydrolysis by means of formic acid was employed. Analytes were baseline-separated within 8 min by using 300 mM tris(hydroxymethyl)aminomethane phosphate pH 3.75 as the running buffer. With use of electrokinetic injection the limit of detection (LOD) in real sample was 0.1 nM, thus improving by about 400-fold the LOD of the previously described methods based on capillary electrophoresis. Sample extraction and purification were optimized so that evaluation of the DNA methylation degree was possible starting from 0.5–1 μg of DNA with intra- and interassay relative standard deviations for the 5-methylcytosine to total cytosine ratio of 2.0 and 3.2%, respectively. Because of its high accuracy and throughput, our method will be useful for large-scale applications to determine the implications of genomic DNA methylation levels in tumorigenesis