Neoadjuvant nivolumab and cabozantinib in advanced renal cell carcinoma in a horseshoe kidney - how to achieve a safe and radical resection? a case report and review of the literature.

Introduction: Neoadjuvant nivolumab and cabozantinib in locally advanced renal cell carcinoma in a horseshoe kidney is a novel therapeutic approach in the preoperative setting. Methods: We report a case of a 52-year old male who presented with a large inoperable tumor of the horseshoe kidney and achieved major partial radiologic response after neoadjuvant therapy with nivolumab and cabozantinib leading to radical resection of the tumor. The patient remains tumor free on the subsequent follow-up and his renal function is only mildly decreased. The systemic treatment was complicated by hepatotoxicity leading to early nivolumab withdrawal. Results: Currently, the combination therapy based on immune checkpoint inhibitors and tyrosine kinase inhibitors represents the treatment of choice in treatment-naïve patients with metastatic renal cell carcinoma in any prognostic group. The neoadjuvant treatment approach is being tested in prospective clinical trials and results are eagerly awaited. Renal cell carcinoma in a horseshoe kidney is an uncommon finding that is always challenging. Additionally, management guidance in this patient population is lacking. In some patients neoadjuvant therapy could be the only way to preserve kidney function. The initial treatment strategy should be individualized to patient needs aiming at the radical resection of the primary tumor as the only chance of getting the tumor under control in the long term. Conclusion: Herein, we highlight the feasibility of neoadjuvant systemic therapy with nivolumab and cabozantinib allowing the subsequent performance of radical tumor resection with negative margins in a patient with advanced renal cell carcinoma in a horseshoe kidney, removing the primary tumor while sparing the patient from lifelong dialysis.

Antineutrophil Cytoplasmic Autoantibody-Associated Glomerulonephritis as a Complication of Home Parenteral Nutrition.

Patients on long-term home parenteral nutrition (HPN) occasionally develop glomerulonephritis due to chronic central venous catheter (CVC)-related infection. Most previously reported cases were membranoproliferative glomerulonephritis (MPGN). This is a case report of a 16-year-old girl receiving HPN for short bowel syndrome. After 11 years on HPN, she developed acute kidney injury with macroscopic hematuria, nephrotic-range proteinuria, and a reduced glomerular filtration rate (GFR). Initially, MPGN associated with chronic bacteremia was suspected with the assumption that the condition would be treated with antibiotics and CVC replacement. However, her kidney biopsy revealed antineutrophil cytoplasmic autoantibody (ANCA)-associated glomerulonephritis (AAG). This was consistent with the fact that the patient tested positive for proteinase 3-ANCA. Immunosuppressive therapy with methylprednisolone pulses (followed by oral prednisone) and rituximab led to remission. Her GFR and protein excretion returned to normal. Chronic bacteremia as a complication of long-term HPN may cause various types of glomerulonephritis including, rarely, AAG requiring immunosuppressive therapy.

Current Status, Prevention and Treatment of BK Virus Nephropathy.

All renal transplant recipients should undergo a regular screening for BK viral (BKV) viremia. Gradual reduction of immunosuppression is recommended in patients with persistent plasma BKV viremia for 3 weeks after the first detection, reflecting the presence of probable or suspected BKV-associated nephropathy. Reduction of immunosuppression is also a primary intervention in biopsy proven nephropathy associated with BKV (BKVN). Thus, allograft biopsy is not required to treat patients with BKV viremia with stabilized graft function. There is a lack of proper randomised clinical trials recommending treatment in the form of switching from tacrolimus to cyclosporin-A, from mycophenolate to mTOR inhibitors or leflunomide, or the additive use of intravenous immunoglobulins, leflunomide or cidofovir. Fluoroquinolones are not recommended for prophylaxis or therapy. There are on-going studies to evaluate the possibility of using a multi-epitope anti-BKV vaccine, administration of BKV-specific T cell immunotherapy, BKV-specific human monoclonal antibody and RNA antisense oligonucleotides. Retransplantation after allograft loss due to BKVN can be successful if BKV viremia is definitively removed, regardless of allograft nephrectomy.

Nephrotoxicity of calcineurin inhibitors as a risk factor for BK polyomavirus replication after kidney transplantation.

BK polyomavirus-associated nephropathy (PyVAN) is responsible for a significant percentage of transplanted kidneys prematurely terminating their function. Its occurrence is closely related to the intensity of immunosuppressive therapy. In a group of 161 newly transplanted patients, we prospectively evaluated 457 protocol renal biopsies performed within the first year after transplantation. Using the calcineurin inhibitors (CI) nephrotoxicity score, the incidence of nephrotoxicity was monitored as a manifestation of excessive immunosuppression. Findings were correlated with clinical evidence of active BK polyomavirus (BKPyV) replication and PyVAN. Compared to the normal histology, nephrotoxicity was associated with more frequent BKPyV viremia and viruria (p = .01 and p < .01, respectively) and more common occurrence of PyVAN. The persistence of toxicity in the subsequent biopsy proved to be a negative risk factor of viremia and viruria (p = .03 and p < .01, respectively), independently of the initial BKPyV status. Toxicity could also be used as a predictor of viremia and viruria (p = .04 and p < .01, respectively) even in the absence of viral replication at the time of initial biopsy. The early histological manifestation of CI nephrotoxicity was associated with significant BKPyV reactivation in the risky first posttransplant year.

Dabrafenib monotherapy in BRAF+ non-small cell lung cancer - our experience.

BACKGROUND: Activating BRAF mutations result in constitutive activation of the MAP kinase signaling cascade, stimulating cell proliferation. BRAF mutations are typical for malignant melanoma, but occur less frequently in other tumors, including in 1-2% cases of non-small cell lung cancer (NSCLC) [1,2]. CASE: We present two case reports of BRAF+ NSCLC patients, treated with 3rd line dabrafenib monotherapy on our department, and also brief review of available information about dabrafenib and its use in monotherapy of BRAF+ NSCLC. CONCLUSION: Monotherapy with BRAF inhibitors presents a viable alternative for BRAF+ NSCLC patients, incapable of combined therapy with trametinib. The lack of proper indication and reimbursement for NSCLC cases remains a problem, and individual treatment approval is required.

Enhanced Oral Bioavailability of 2-(Phosphonomethyl)-pentanedioic Acid (2-PMPA) from its (5-Methyl-2-oxo-1,3-dioxol-4-yl)methyl (ODOL)-Based Prodrugs.

2-(Phosphonomethyl)-pentanedioic acid (2-PMPA) is a potent (IC50 = 300 pM) and selective inhibitor of glutamate carboxypeptidase II (GCPII) with efficacy in multiple neurological and psychiatric disease preclinical models and more recently in models of inflammatory bowel disease (IBD) and cancer. 2-PMPA (1), however, has not been clinically developed due to its poor oral bioavailability (<1%) imparted by its four acidic functionalities (c Log P = -1.14). In an attempt to improve the oral bioavailability of 2-PMPA, we explored a prodrug approach using (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (ODOL), an FDA-approved promoiety, and systematically masked two (2), three (3), or all four (4) of its acidic groups. The prodrugs were evaluated for in vitro stability and in vivo pharmacokinetics in mice and dog. Prodrugs 2, 3, and 4 were found to be moderately stable at pH 7.4 in phosphate-buffered saline (57, 63, and 54% remaining at 1 h, respectively), but rapidly hydrolyzed in plasma and liver microsomes, across species. In vivo, in a single time-point screening study in mice, 10 mg/kg 2-PMPA equivalent doses of 2, 3, and 4 delivered significantly higher 2-PMPA plasma concentrations (3.65 ± 0.37, 3.56 ± 0.46, and 17.3 ± 5.03 nmol/mL, respectively) versus 2-PMPA (0.25 ± 0.02 nmol/mL). Given that prodrug 4 delivered the highest 2-PMPA levels, we next evaluated it in an extended time-course pharmacokinetic study in mice. 4 demonstrated an 80-fold enhancement in exposure versus oral 2-PMPA (AUC0-t: 52.1 ± 5.9 versus 0.65 ± 0.13 h*nmol/mL) with a calculated absolute oral bioavailability of 50%. In mouse brain, 4 showed similar exposures to that achieved with the IV route (1.2 ± 0.2 versus 1.6 ± 0.2 h*nmol/g). Further, in dogs, relative to orally administered 2-PMPA, 4 delivered a 44-fold enhanced 2-PMPA plasma exposure (AUC0-t for 4: 62.6 h*nmol/mL versus AUC0-t for 2-PMPA: 1.44 h*nmol/mL). These results suggest that ODOL promoieties can serve as a promising strategy for enhancing the oral bioavailability of multiply charged compounds, such as 2-PMPA, and enable its clinical translation.

Sphingosine kinase-1 predicts overall survival outcomes in non-small cell lung cancer patients treated with carboplatin and navelbine.

Sphingosine 1-phosphate (S1P) is a bioactive lipid metabolite associated with cancer cell proliferation, survival, migration and regulation of tumor angiogenesis in various cellular and animal models. Sphingosine kinase-1 (SphK1) and S1P lyase are the main enzymes that respectively control the synthesis and degradation of S1P. The present study analyzed the prognostic and predictive value of SphK1 and S1P lyase expression in patients with non-small cell lung cancer (NSCLC), treated with either surgery alone or in combination with adjuvant carboplatin and navelbine. Formalin-fixed, paraffin-embedded tissue samples from 176 patients with NSCLC were stained immunohistochemically using antibodies against SphK1 and S1P lyase, and their expression was correlated with all available clinicopathological factors. Increased expression of SphK1 was significantly associated with shorter overall and disease free survival in patients treated with adjuvant platinum-based chemotherapy. No prognostic relevance for S1P lyase expression was observed. Collectively, the results suggest that the immunohistochemical detection of SphK1 may be a promising predictive marker in NSCLC patients treated with adjuvant platinum-based chemotherapy.

Real life adjuvant chemotherapy uptake and survival in patients with non-small cell lung cancer after complete resection.

OBJECTIVES: Adjuvant chemotherapy (AC) in non-small cell lung cancer (NSCLC) has become a standard of care in patients with stages IIA, IIB, and IIIA after complete tumor resection. Utilization and outcome of AC in routine practice is described in a few studies, with non-conclusive results. MATERIALS AND METHODS: This retrospective study included consecutive patients with NSCLC who underwent curative-intent surgery. Data of AC uptake in stages IB (tumor of ≥4 cm in diameter), II, and IIIA, and reasons of AC omission were evaluated according to medical records. Mortality risk among patients treated with surgery (only) and different types of AC in routine practice was compared. RESULTS: AC was applied to 79% of patients with stages IB (tumor of ≥4 cm in diameter), II, and IIIA, and was associated with an improved median of overall survival (HR = 0.69; 95% CI = 0.44-1.06). Significantly longer survival was achieved in the sub-group treated with platinum and oral vinorelbine (HR = 0.575, 95% CI = 0.339-0.974), and the longest survival was among patients treated with oral vinorelbine and cisplatin (HR = 0.371, 95% CI = 0.168-0.820). CONCLUSIONS: AC utilization should be based on co-operation between surgeons, pneumo-oncologists, and patients. Rational use of AC offers better survival in routine practice.

BK virus-induced renal allograft nephropathy.

BK virus nephropathy (BKVN) is a serious opportunistic infection threatening renal function especially during the first year after transplantation. Its incidence is now on the rise and is closely related to the level of the recipient's immune system inhibition. This is more intensive with current trends in transplantation medicine, where more potent immunosuppressive protocols are used and more aggressive antirejection therapy is applied. In the absence of BK virus (BKV) specific therapy and limited treatment options for advanced BKVN, active screening of BKV replication and subsequent preemptive adjustment of immunosuppression are essential measures to prevent BKVN. However, it remains unclear how to modify immunosuppressive protocols as well as how to address initial stages of BKV replication. This comprehensive review summarizes the currently applied and not completely uniform procedures for the detection, prophylaxis and therapy of BKV replication and BKVN. The pitfalls brought by reduced immunosuppression, as a typical response to a significant viral replication or a developed BKVN, are also mentioned, particularly in the form of graft rejection. The paper also outlines the authors' experiences, and lists currently ongoing studies on the subject. The perspectives of new, especially immune-based, procedures in the treatment of complications associated with BKV infections are highlighted. Different views on the management of patients indicated for kidney re-transplantation whose previous graft failed because of BKVN are also discussed.

N-Substituted Prodrugs of Mebendazole Provide Improved Aqueous Solubility and Oral Bioavailability in Mice and Dogs.

Mebendazole (MBZ) was developed as a broad-spectrum anthelmintic but has recently shown efficacy as an anticancer agent. The use of MBZ for cancer, however, is challenging due to its poor solubility leading to poor bioavailability. Herein, we developed a prodrug approach with various N-linked promoieties including acyloxymethyl, aminoacyloxymethyl, and substituted phosphonooxymethyl in attempt to improve these characteristics. Compound 12, containing an (((((isopropoxycarbonyl)oxy)methoxy)phosphoryl)oxy)methyl promoiety, showed a >10 000-fold improvement in aqueous solubility. When evaluated in mice, 12 displayed a 2.2-fold higher plasma AUC0- t and a 1.7-fold improvement in brain AUC0- t with a calculated oral bioavailability of 52%, as compared to 24% for MBZ-polymorph C (MBZ-C), the most bioavailable polymorph. In dogs, 12 showed a 3.8-fold higher plasma AUC0- t with oral bioavailability of 41% compared to 11% for MBZ-C. In summary, we have identified a prodrug of MBZ with better physicochemical properties and enhanced bioavailability in both mice and dog.

Prognostic Influence of Internal Mammary Node Drainage in Patients with Early-stage Breast Cancer.

BACKGROUND: The management of internal mammary nodes (IMNs) during multidisciplinary treatment of breast cancer has been debated for the last four decades without unequivocal conclusion. PATIENTS AND METHODS: We retrospectively reviewed patients with breast cancer who underwent sentinel lymph node biopsy at our center from 2008 until 2012. IMN drainage was assessed as a potential risk factor for local and distant disease recurrence. RESULTS: We identified 712 patients, with incidence of drainage to IMNs of 18.4%. No detrimental effect of the pattern of drainage to IMNs was found after a median follow-up of 58 months. A similar outcome was observed when drainage to IMNs was evaluated as a risk factor for patient survival. The potential risk factors for drainage to IMNs during sentinel lymph node biopsy were younger age (p=0.002) and tumor location in lower-outer, lower-inner, and upper-inner versus upper-outer quadrant (p<0.0001). CONCLUSION: The drainage to IMNs is unlikely to have a detrimental effect on patient outcome.

High-grade urothelial bladder cancer in children: A case report and critical analysis of the literature.

BACKGROUND: Bladder cancer is relatively common in adults. In children, it is extremely rare and in the majority of cases, low grade, low stage urothelial cancers are found. CASE REPORT: We describe the diagnostic, therapeutic, and follow-up management of bladder cancer in a 3-year-old boy examined for painless hematuria. Transurethral resection of the tumor was performed and T1 high grade urothelial cancer with osseous metaplasia was found in definitive specimens. During the 2-year follow-up, there has been no recurrence. Typical characteristics of the most prevalent bladder tumors are presented. CONCLUSION: Despite its low incidence and low prevalence bladder cancer in children is a very serious condition which must not be missed in the differential diagnosis of hematuria or urinary tract infection. It is vital to differentiate urothelial cancer from hamartoma and nephrogenic adenoma and, particularly in osseous metaplasia, from sarcomatoid carcinoma. Especially in high-grade cancers, precise TUR of the tumor with a careful follow-up is essential to detect cancer recurrence and reduce progression.

Evaluation of Lumbar Spine Load by Computational Method in Order to Acknowledge Low-back Disorders as Occupational Diseases.

AIM: The aim of the study was to develop a computational module for the prediction of compressive force on the L4/L5 disc suitable for use in field settings. METHOD: The value of compressive force is intended to be used as a proxy measure of the mechanical burden of low-back when performing work activities. The compressive force predicted by the module in a particular worker should be compared with the NIOSH limit value of 3,400 N for the assessment of lumbar spine load during manual lifting tasks. Exceeding the limit will be considered as the fulfilment of "hygienic criterion" that should be met to acknowledge low-back disorder as an occupational disease. To develop the computational module we used the ergonomic software TECNOMATIX Classic Jack taking into account the anthropometric parameters of a worker and ergonomic parameters of his/her work activity. RESULTS: We calculated compressive forces on the L4/L5 disc in about 1,300 simulated combinations of various factors influencing compressive force. Parameters which turned out to be crucial for the compression of L4/L5 disc were included in the computational algorithm. CONCLUSION: Our study was primarily aimed at the assessment of lumbar disorders as occupational diseases. Moreover, the study can contribute to the recommendation of preventive measures to decrease health risks in occupations associated with the overload of low-back region. The graphic maps generated by the computational module enable a fast and exact analysis of particular job.

Sarcoidosis of female reproductive organs in a postmenopausal woman: a case report and review of the literature: is there a potential for hormone therapy?

OBJECTIVE: Sarcoidosis is a multisystem inflammatory disorder of unknown cause that affects multiple organs. To date, only isolated cases of extrapulmonary sarcoidosis of the female reproductive tract, which rarely affects postmenopausal women, have been reported. METHODS: We describe the case of a postmenopausal woman with sarcoidosis of multiple structures of the genital tract accompanied by pulmonary involvement. A review of the literature was performed to examine the role of sex hormones in the pathogenesis of sarcoidosis. RESULTS: We describe the case of a 60-year-old white, nulliparous, nulligravid postmenopausal woman with sarcoidosis of the cervix, uterus, mesosalpinx, and right ovary, accompanied by pulmonary involvement. The diagnosis was based on the identification of noncaseating granulomas in reproductive tract organs. Although imaging methods (high-resolution CT and chest x-ray) and pulmonary function tests did not reveal any abnormality, lung involvement was confirmed histologically by transbronchial biopsy. Treatment with steroids was successful and led to normalization of serum biomarker (serum angiotensin-converting enzyme, soluble interleukin-2 receptor, and neopterin) levels. CONCLUSIONS: This particular case and a brief literature review of female genital tract sarcoidosis in postmenopausal women suggest the role of sex hormones in the pathogenesis of sarcoidosis. Hormone therapy may be a prospective therapeutic alternative to corticosteroids in postmenopausal women.

Primitive neuroectodermal tumor (PNET) of the lung in an adult woman.

Primary primitive neuroectodermal tumors (PNETs) are extremely rare in the lung and especially in adult women. We describe a case of PNET of the lung with aggressive behavior in 31-year-old woman. Diagnosis was based on histopathological and immunohistochemical studies, and confirmed by molecular genetic analysis of chromosome rearrangements in the EWSR1 gene region. Clinical follow-up, post-mortem findings, and differential diagnosis are also discussed.

[Bortezomib-based therapy in patients with light chain deposition disease]. / Lécba bortezomibem u pacientu s onemocnením z depozice lehkých retezcu imunoglobulinu.

Light chain deposition disease (LCDD) is a rare systemic condition caused by monoclonal proliferation of terminally differentiated B-lymphocytes with production of free light chains and their deposition in kidneys or other organs. The aim of our study is to show the pitfalls of the diagnostics, and to demonstrate the effect of bortezomib-based therapy on a series of 4 patients with LCDD, from the point of hematological and organ therapeutic response. We include that bortezomib based treatment provides rapid and effective hematological response. It is, however, often accompanied by adverse events, especially within intensive treatment schedules. The most serious adverse effects includes peripheral neuropathy, which might be dose or treatment-limiting. Less intensive regimens ("bortezomib weekly") suggest an alternative with expectation of lower incidence of adverse effects. Autologous stem cell transplantation is a recommended and relatively safe approach in convenient candidates. Organ response is significantly delayed after hematological response, and organ damage by light chain deposits might not be fully reversible.

[Closed pleural biopsy in the diagnostics of malignant pleural involvement]. / Necílená biopsie pleury v diagnostice maligního pleurálního výpotku - nase zkusenosti za posledních 15 let.

INTRODUCTION: Pleural effusion is a frequent reason for a pulmonologist´s investigation. The cornerstone is to distinguish transudative pleural effusion from exudative pleural effusion. In the case of the exudative pleural effusion the next step is detection of malignant etiology of pleural effusion. We have a variety of any non-invasive or invasive examinations. The pleural biopsy is one of the most important methods for diagnostics of malignant pleural effusion. MATERIAL AND METHODS: Two hundred and twenty-two closed pleural biopsies (CPB) were performed in 208 patients with pleural effusion, where the cytologic examination of pleural fluid was negative. The authors evaluated the value of CPB for the diagnosis of malignant pleural involvement. RESULTS AND CONCLUSION: Total sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 63.1%, 100%, 73.9%, 100% and 52.8%, but in the group of mesotheliomas these results were 59.1%, 100%, 79.4%, 100% and 70.7%. The incidence of complications and representative sampling of the pleura was mentioned. The authors compared the diagnostic value and the incidence of complications of various diagnostic methods in malignant pleural involvement by data in the literature.

Foamy cell (hibernoma-like) change is a rare histopathological feature in renal cell carcinoma.

We report nine patients (seven males and two females, median age 64 years (range 51-79 years)) with a renal cell carcinoma, each of which contained a significant component of neoplastic epithelial cells with a striking microvacuolated (hibernoma-like) cytoplasmic appearance. Tumor sizes ranged from 1.5 to 8.0 cm (mean 4.2 cm, median 4.3 cm). The basic architecture of the tumors was solid-alveolar in two cases (classified as renal cell carcinoma-not otherwise specified (NOS)) and papillary in seven cases (classified as papillary renal cell carcinoma NOS). The nuclear grade according to the Fuhrman grading system was three in all cases. By immunohistochemistry, the cells with microvacuolated cytopasm and significantly expressed adipophilin and anti-mitochondrial antigen in a similar cytoplasmic pattern. On ultrastructural examination, the cytoplasm of the neoplastic epithelial cells was packed with distended mitochondria, most of which displayed lamellated cristae. Numerous microvesicles were dispersed between the mitochondria. No mutations in the succinate dehydrogenase B gene were identified. Based on our findings, we propose that the mechanism behind this phenomenon is an abnormal intracellular processing of lipids. No aggressive behavior was observed in six out of nine patients with available follow-up information.

Adrenal disease: a clinical update and overview of imaging. A review.

AIM: The aim of this article is to provide an overview of the most frequent clinically significant adrenal diseases and to describe the latest trends in their diagnostics, particularly by means of imaging techniques. METHODS: The authors reviewed standard textbooks and subsequently conducted a search using the PubMed (Public/Publisher MEDLINE) electronic database by the year 2013 with the following search terms: adrenal masses, adrenal adenoma, phaeochromocytoma, adrenocortical carcinoma, metastases, incidentalomas, hypercortisolism, hyperaldosteronism. RESULTS: If adrenal disease is clinically suspected, hormone tests are performed to detect adrenal hyperfunction and imaging studies are used to assess the nature of adrenal lesion. The most frequent syndromes include hypercortisolism, primary hyperaldosteronism, and phaeochromocytoma. The clinically most significant pathologies of the adrenal glands are adenomas and adrenal hyperplasia, adrenocortical carcinomas, phaeochromocytomas, and metastases. Given the availability and improved quality of imaging techniques, adrenal incidentalomas are detected increasingly often. In these cases, it is necessary to rule out hormonal activity and malignancy. Incidentalomas can be associated with clinical syndromes of adrenal hormone overproduction. In most cases, they are clinically silent. In some cases, the definitive diagnosis can be determined as early as during the initial examination with an imaging technique (most frequently, a CT scan). If the finding is inconsistent, other imaging techniques can be used: CT contrast washout analysis, MRI, SPECT or PET/CT. CONCLUSION: In the case of adrenal gland disorders, correct interpretation of the results of laboratory tests and imaging studies is essential for further management of these patients.

Pediatric parotideomasseteric pilomatrixoma in children.

AIMS: To review definitive histological diagnoses of patients with great salivary gland tumors with focus on the relatively high incidence of pediatric pilomatrixomas. The authors focus on clinical investigation, imaging methods and fine needle aspiration cytology of pilomatrixomas. METHODS: We treated 12 children with great salivary gland masses aged from 6 months to 18 years from 1995 to 2010. The records of these patients were reviewed to determine sex, age, clinical presentation, and histological findings. RESULTS: Among children having true neoplasms, there was a prevalence of carcinomas (6 out of 9), with low-grade mucoepidermoid and acinic cell carcinomas (two each) as the dominating histopathological diagnosis. There was one adenoid cystic carcinoma and one curious undifferentiated carcinoma in a 6 month old baby. Among all 6 benign lesions, accounting for a half of the total, pilomatrixoma was the most common (2 out of 6) diagnosis, representing 17% (2 out of 12) of all salivary gland lumps and 66% (2 out of 3) of all true benign neoplasms. CONCLUSIONS: Pilomatrixoma should be included in the differential diagnosis of pediatric parotideomasseteric lumps. Clinical investigation reveals adherence to the skin but not to the underlying tissue. Clinical assessment and ultrasound guided fine needle aspiration cytology in typical findings strongly support the diagnosis. Cytopathologists must be aware of the preliminary diagnosis of a pilomatrixoma to use proper fixation of the smears. In doubts, frozen biopsy must be sent before parotidectomy is performed.