[Parametric monitoring of the quality of total mesorectal excision and surgical treatment of rectal carcinoma results of a multicenter study]

INTRODUCTION

Tumour size and the quality of its complete surgical removal are the main prognostic factors in rectal cancer treatment. The number of postoperative local recurrences depends on whether the mesorectum has been completely removed - total mesorectal excision (TME) - and whether tumour-free resection margins have been achieved. The surgery itself and its quality depend on the accuracy of preoperative diagnosis and detection of risk areas in the rectum and mesorectum, on the surgeons skills, and finally on pathological assessment evaluating whether complete tumour excision has been accomplished including circumferential margins of the tumour, and whether mesorectal excision is complete. The aim of our study was to implement and standardize a new method of evaluation of the quality of the surgical procedure - TME - in rectal cancer treatment using an assessment of its circumferential margins (CRO) and completeness of the excision.

METHODS

The study consisted of two parts. The first, multi-centre retrospective phase with 288 patients analysed individual partial parameters of the diagnosis, operations and histological examinations of the rectal cancer. Critical points were identified and a unified follow-up protocol was prepared. In the second, prospective part of this study 600 patients were monitored parametrically focusing on the quality of the TME and its effect on the oncological treatment results.

RESULTS

The proportion of patients with restaging following neoadjuvant therapy increased from 60.0% to 81.7% based on preoperative diagnosis. The number of specimens missing an assessment of the mesorectal excision quality decreased from 52.9% in the retrospective part of to the study to 22.8% in the prospective part. The proportion of actually complete TMEs rose from 22.6% to 26.0%, and that of nearly complete TMEs from 10.1% to 24.0%.

CONCLUSION

The introduction of parametric monitoring into routine clinical practice improved the quality of pre-treatment and preoperative diagnosis, examination of the tissue specimen, and consequently improved quality of the surgical procedure was achieved.

KEY WORDS

rectal cancer TME - parametric monitoring - quality control.

[Technical background of data collection for parametric observation of total mesorectal excision (TME) in rectal cancer]

INTRODUCTION

Improvement in any human activity is preconditioned by inspection of results and providing feedback used for modification of the processes applied. Comparison of experts experience in the given field is another indispensable part leading to optimisation and improvement of processes, and optimally to implementation of standards. For the purpose of objective comparison and assessment of the processes, it is always necessary to describe the processes in a parametric way, to obtain representative data, to assess the achieved results, and to provide unquestionable and data-driven feedback based on such analysis. This may lead to a consensus on the definition of standards in the given area of health care.

METHOD

Total mesorectal excision (TME) is a standard procedure of rectal cancer (C20) surgical treatment. However, the quality of performed procedures varies in different health care facilities, which is given, among others, by internal processes and surgeons experience. Assessment of surgical treatment results is therefore of key importance. A pathologist who assesses the resected tissue can provide valuable feedback in this respect.

RESULTS

An information system for the parametric assessment of TME performance is described in our article, including technical background in the form of a multicentre clinical registry and the structure of observed parameters.

CONCLUSION

We consider the proposed system of TME parametric assessment as significant for improvement of TME performance, aimed at reducing local recurrences and at improving the overall prognosis of patients.

KEY WORDS

rectal cancer total mesorectal excision parametric data clinical registries TME registry.

[Predicting pN positivity in T3 rectal cancer]

INTRODUCTION

Stage pN+ is a factor which determines the strategy for treatment of T3 rectal cancer. The sensitivity of preoperative imaging examinations revealing N+ is not entirely satisfactory. Risk factors that are associated with pT3pN+ stage and that are detectable by preoperative examination have not been reliably identified. The aim of the study is to analyze the predictive factors determining lymph node involvement in T3 rectal cancer.

MATERIAL AND METHODS

Patients with rectal resection for (y)pT3 rectal cancer were analysed. All of the surgical interventions were performed at the Department of Surgery, University Hospital in Hradec Kralove, from 1 January 2011 to 28 February 2014. Data were prospectively collected and saved in the Rectal Cancer Oncologic Register. The parameters studied were age, gender, tumour localisation and its circumferential topography, preoperative chemoradiotherapy, absolute number of harvested lymph nodes and the number of positive lymph nodes in each specimen, tumour grading, presence of lymphovascular invasion and perineural invasion, and the depth of tumour penetration.

RESULTS

After selection, 89 patients with T3 rectal cancer were included into the study. Resection for cancer of the upper rectum was performed in 22 (24.7%) patients, middle rectum in 37 (41.6 %) and lower rectum in 30 (33.7%) patients. 38 (42.7%) patients underwent primary operation, 41 (46.1%) patients received neoadjuvant chemoradiotherapy, and radiation therapy was administered to only 10 (11.2%) patients. Stage pN+ was found in 51 (57.3%) patients. Statistical analysis was used to identify the risk factors for pN+: lymphovascular invasion (p0.001), angioinvasion (p=0.030) and perineural invasion (p=0.010). On the border of statistical significance for pN+, low grading of the tumour (p=0.084) was found. The depth of penetration of the tumour into the mesorectum was not statistically significant (p=0.230).

CONCLUSION

Our study has shown that pN positivity is associated with lymphovascular invasion, perineural invasion and low grading of the tumour. Accurate identification of these factors before treatment, however, remains very difficult.

[Evaluation of safe resection margins in rectal carcinoma]

The fact that surgically well performed total mesorectal excision with negative circumferential resection margin represents one of the most important prognostic factors in colorectal carcinoma is already well known. These parameters significantly affect the incidence of local tumour recurrence as well as distant metastasis, and are thus related to the duration of patient survival. The surgeons task is to perform mesorectal excision as completely as possible, i.e., to remove the rectum with an intact cylinder of mesorectal fat. The approach of the pathologist to evaluation of total mesorectal excision specimens differs greatly from that of resection specimens from other parts of the large bowel. Besides evaluation of the usual parameters for colon cancer staging, it is essential to assess certain additional factors specific to rectal carcinomas, namely tumour distance from circumferential (radial) resection margins and the quality of the mesorectal excision. In order to accurately evaluate these parameters, knowledge of a wide range of clinical data is indispensable (results of preoperative imaging, intraoperative findings). For objective evaluation of these parameters it is necessary to introduce standardized procedures for resection specimen processing and macro and microscopic examination. This approach is based mainly on standardized macroscopic photo-documentation of the integrity of the mesorectal surface. Parallel transverse sections of the resection specimens are made with targeted tissue sampling for histological examination. It is essential to have close cooperation between surgeons and pathologists within a multidisciplinary team enabling mutual feedback.

[Rectal cancer within 10 cm. Comparison of the radicality of laparoscopic and open surgical techniques with regard to the circumferential resection margin and the completeness of mesorectal excision]

INTRODUCTION

The issue of achieving radical circumferential margin in laparoscopic rectal surgery has not yet been satisfactorily clarified. In this paper we have focused on circumferential margin assessment and the quality of the mesorectal excision, comparing laparoscopic and open resection for cancer of the middle and lower rectum.

MATERIAL AND METHODS

The results of surgical procedures for middle and low rectal cancer were analysed. All the interventions were performed at the Department of Surgery, Teaching Hospital in Hradec Kralove, during the period from January 2011 to December 2012. The data were prospectively collected and entered in the Rectal Cancer Registry. Age, gender, BMI, tumour localisation and topography, the clinical stage, preoperative chemoradiotherapy and response to it, the type of surgery, distal and circumferential margin characteristics, mesorectal excision quality, pT and pN were compared for laparoscopic and open surgery.

RESULTS

A total of 161 patients were operated on for rectal cancer during the abovementioned period. 94 patients were included in the trial following selection. Laparoscopy was used in 40 patients and open surgery in 54 patients. Laparoscopic approach was performed in 33 (82.5%) low anterior resections (including four intersphincteric resections), 6 (15%) abdominoperineal amputations and 1 (2.5%) Hartmanns procedure. Open surgery was used for 26 (48.1%) low anterior resections, 21 (38.9%) APR and 7 (13%) Hartmanns procedures. Complete mesorectal excision was achieved in 45% of the laparoscopic resections vs. 46.3% of open resections. Nearly complete excision was performed in 22.5% and 11.1%, respectively. Finally, incomplete excision was described in 30% vs. 38.9%. No available data for TME was detected in three patients. The differences in TME were not statistically significant. Positive circumferential margin was found in 5 (12.5%) patients in the laparoscopy group; on the contrary, in the group undergoing open surgery, pCRO+ was found in 15 (27.8%) patients. Here, too, the results were not statistically significant. When patients without preoperative chemoradiotherapy were excluded, the relationship between ypCRM in the laparoscopy and open surgery group was on the border of statistical significance (Fischer=0.0556).

CONCLUSION

As has been shown in our trial, the outcomes of laparoscopic and open approach in rectal cancer treatment are very similar. Particularly, mesorectal excision quality and negative CRM results have proven that the laparoscopic technique is safe and comparable to open surgery in rectal cancer treatment.

[The radicality of surgical resection in rectal cancer. Analysis of factors associated with incomplete mesorectal excision]

INTRODUCTION

Circumferential resection margin (pCRM) and the completeness of mesorectal excision (ME) are two independent prognostic factors significantly associated with the radicality of surgical treatment. Positive pCRM and incomplete mesorectal excision are associated with a significantly higher incidence of local recurrence and worse patient prognosis. The aim of this article is to analyze the risk factors associated with incomplete mesorectal excision.

MATERIAL AND METHODS

Patients operated on at the Department of Surgery, University Hospital Hradec Kralove between January 2011 and February 2013 were included in the study. The patients data were prospectively collected and entered in the Dg C20 registry. The following factors were analyzed: sex, age, BMI, cN, pT, clinical stage, the involved segment of the rectum, neoadjuvant therapy, circumferential tumour location, the type of surgical approach and the type of surgery.

RESULTS

168 patients were operated on during the above period. 9 (5.3%) palliative stomas and 159 (94.6%) resection procedures were performed in this group of 168 patients. 7 (4.4%) patients were excluded because the quality of excision was not assessed in them. 114 (75%) resections, including 5 intersphincteric resections, were performed in the group of the remaining 152 patients. 10 (7%) were Hartmanns procedures a 28 (18%) were amputation procedures. Out of 152 procedures, 69 (45%) were performed laparoscopically. Positive (y)pCRO was recorded in 26 (17%) patients, predominantly after abdominoperineal resection (APR) - 11 out of 27 (41%), and Hartmanns operation - 6 out of 10 (60%). Incomplete ME was observed in 45 patients (30%), complete ME in 81 patients (53%) and partially complete in 26 patients (17%). Univariate analysis confirmed statistically significant factors associated with incomplete mesorectal excision: (y)pT (P = 0.00027), type of surgery (P = 0.00001) and tumour location (P = 0.00001). Multivariate analysis then confirmed two independent prognostic factors associated with incomplete mesorectal excision. It was the location of the tumour in the distal third of the rectum and the (y)pT stage of the tumour.

CONCLUSION

Distal rectum tumor location and higher (y)pT are associated with a higher risk of incomplete mesorectal excision with worse patient prognosis.

[Predictive diagnosis of breast cancer]

Detection of selected predictive markers is currently included in the standard diagnostic algorithm of breast carcinoma specimens. Despite this fact we are facing several unresolved questions and issues. Probably the most frequently discussed predictive marker in breast carcinoma is HER-2/neu. The change of criteria of positivity in 2007 brought several confusions regarding the selection of patients eligible for anti-HER2 treatment. There is a deficiency of knowledge in tumors with the discordant phenotype (a discrepancy between the results of immunohistochemistry and in situ hybridization). Even in selected HER2 positive patients is the anti-HER2 treatment effective in only 30 % of cases. Thus, we evidently have to search for new markers which would help to more precisely select the optimal treatment for breast cancer patients.

[Predictive factors for non-sentinel lymph nodes affection in breast carcinoma--outcomes of a Czech multicenter study of sentinel lymph nodes]

BACKGROUND

The aim of the study was to assess positivity nonsentinel lymph nodes in patients with macro, micro and submicrometastases in sentinel lymph nodes and find predictive factors of positivity nonsentinel lymph nodes. Study was conducted at the Department of Surgery in Pardubice, Pilsen, Ostrava and Zlín.

MATERIAL AND METHODS

Sentinel lymph nodes were assessed based on standards of Czech Pathological Society. Detection of sentinel lymph nodes was performed based on radionavigation or combination of radionavigation and blue dye method.

RESULTS

In group N1 (macrometastases) there was found positivity of nonsentinel lymph nodes in 50% (45 from 90 patients). In group N1 Mi (micrometastases) there was found positivity of nonsentinel lymph nodes in 26.7% (16 from 60 patients). In group NO I+ (sub-micrometastases) there was found positivity of nonsentinel lymph nodes in 6.7% (1 from 15 patients). Predictive factors were size of metastasis, number of positive sentinel lymph nodes and grading. Size of tumor was not found to be a predictive factor of positivity nonsentinel lymph nodes.

DISCUSSION

High positivity of nonsentinel lymph nodes in pacients with macro and micrometastases in sentinel lymph nodes advocates to perform axillary lymph nodes dissection. Due to small number of patients with submicrometastases it is not possible to assess if axillary dissection is necessary or not. Predictive factors of positivity of nonsentinel lymph nodes are size of metastasis in sentinel lymph nodes, number of positive sentinel lymph nodes and grading. Size of tumor was not found to be a predictive factor due to small tumors in the study. In spite of this it is necessary to consider it like a predictive factor of positivity nonsentinel lymph nodes.

CONCLUSION

In patients with macro and micrometastases it is necessary to perform axillary dissection. In patients with submicrometastases in sentinel lymph nodes it is necessary to consider predictive factors.

[Metanephric adenoma. 11 case reports and detection of collagen spherules in one tumor]

Eleven cases of metanephric adenoma are reported. The tumors were selected out of 6500 tumorous and pseudotumorous lesions of the kidney in our registry. Female to male ratio was 1:1.2. The average age of the patients was 48.3 years, with a range of 13-79 years. The mean size of the tumors was 7.2 cm. The tumors were spherical in shape, whitish to yellowish in colour. Histologically, they were arranged in a mainly tubular pattern with short pseudopapillae. The tumorous cells were deeply eosinophilic to basophilic with predominantly round nuclei. Psammomatous bodies were numerous. Immunohistochemically, they reacted positively with antibodies against cytokeratins, vimentin, and WT1. Ultrastructurally, the cytoplasm contained mitochondria, RER, and ribosomes. A collagenous spherulosis, identical with those in salivary gland and mammary tumors, was revealed in one case. The spherules were located mainly inside tubular structures. Ultrastructurally, they were composed of basement membrane-like material, which was surrounded by epithelial cells. Follow-up all of our patients was negative (if known) for 10 months to 4 years.

[Role of the MIB-1 proliferative markers in the diagnosis and prognosis of tumors of the thyroid gland]

Well-differentiated thyroid tumors may sometimes cause diagnostic uncertainty due to difficulties in the evaluation of certain morphological criteria (capsular and/or vascular invasion, cytomorphological features). Therefore, various diagnostic/prognostic markers are currently studied, namely the markers of tumor proliferation. The aim of our study was to evaluate the proliferative MIB-1 index in 155 thyroid tumors, and to correlate it with morphological diagnosis, size of the tumors, and the patients' age. Oncocytic tumors were represented by 59 follicular adenomas, 27 follicular carcinomas and 12 papillocarcinomas. Nononcocytic tumors comprised 24 follicular adenomas and 33 conventional papillary carcinomas. The Ki-67 antigen (formalin resistant epitope MIB-1) was detected immunohistochemically and the proliferative index (PI) of tumors was evaluated. The results were statistically analyzed using analysis of variance (ANOVA) and Wilcoxon tests (significance level p < 0.05). Carcinomas showed significantly higher PI than adenomas. Moreover, PI in oncocytic adenomas was higher than in nononcocytic ones. However, proliferative activity in all types of the carcinomas was similar. The higher rates of proliferation correlated with the advanced age of the patients with follicular carcinomas (p < 0.0016).

[Angiogenesis in breast carcinoma. Immunohistochemical study of 142 cases]

Due to the fact that capillary vessels provide not only supply of nutrients to the tumor but also represent a gate for lymphogenous and hematogenous metastatic spreading of the tumor, angiogenesis has gained increasing attention in recent years. The aim of the project was: 1. to study number of capillaries in the tumor and its relationship to the metastatic potency and prognosis and 2. to analyse the differences in the quantity of the capillaries between the groups of tumors with or without previously performed aspiration biopsy. 142 cases of breast carcinoma diagnosed at the Fingerland's Department of Pathology in the years 1997-98 were examined. Endothelial cells were visualized immunohistochemically using an antibody against factor VIII (von Willebrand factor). Capillary vessels were counted at 200x magnification (using eyepiece graticule) in the areas of highest angiogenic activity (hot spots), usually at the periphery of the tumor. The highest microvessel counts (HMC) were correlated with other factors (age, tumor size, grade, nodal status, expression of hormonal receptors, proliferative activity, p53, HER-2/neu). The differences between the tumors with and without previous aspiration biopsy were analyzed. All patients were women aged 31-86 years (median 59). The size of tumors was 4-70 mm (median 20 mm). Sixty cases have been previously examined by fine needle aspiration cytology; 72 cases were node-positive. HMC values varied from 26 to 185 (average 63.9, median 60) per microscopic field (area 0.24 mm2). The HMC was significantly higher in node-positive tumors (median 57.5 versus 66; p = 0.036). The capillary vessel counts did not correlate with other parameters examined. Fine needle aspiration cytology does seem to increase the number of intratumoral capillary vessels only for a transitory period. We have also compared HMC/mm2 in normal breast tissue with counts in carcinoma. Interestingly, the values in normal lobules, were significantly higher (median 565 versus 243; p < 0.0000001).

Sclerosing papillary carcinoma of the thyroid with tubular features

A case of papillary thyroid carcinoma (PTC) in a twenty-seven year old female is reported. The patient presented with complaints of a goiter and associated dysphagia. Histologically, the tumor was characterized by diffuse growth of branching tubules lined by a single layer of the tumor cells and surrounded by circularly arranged fibrous tissue of variable thickness. Focally, micropapillary projections of the epithelium budding into the lumen of tubules were visible. The cells showed features of PTC (overlapping ground glass nuclei, multiple grooves and pseudoinclusions). Nevertheless, no areas of "classical" PTC were identified. A striking feature was the presence of a severe lymphoplasmocytic infiltrate and the presence of plentiful S-100 protein positive dendritic/Langerhans cells. The tumor shares several features with diffuse sclerosing PTC, namely the age and sex of the patient, the infiltrative growth pattern and the presence of severe chronic thyroiditis that is associated with a large number of dendritic/Langerhans cells in the background. There are, however, several distinct differences - particularly the absence of massive squamous metaplasia, psammoma bodies, areas of classical PTC, and also lack of invasion of lymphatic vessels. We believe that this tumor represents an unusual example of diffuse sclerosing PTC with special tubular features.

[Angiogenesis in tumors. Part II. Methods and significance of quantification; angiogenesis as a prognostic indicator and the target of therapeutic approaches]

The efforts to quantify tumor angiogenesis (AG) have been limited by the methods available. Only since introduction of immunohistochemistry, detection of early stages of capillary vessel formation is enabled. There were reports showing strong correlation between AG and behavior of the tumor (namely formation of metastases, disease free interval, and overall survival) particularly in carcinomas of the breast, prostate, esophagus, stomach and colon. However, significance of these studies is strongly dependent on the methodological aspects, e.g. the choice of visualized endothelial antigen, microscopic magnification and selection of areas with highest angiogenic activity (so called "hot spots"). We present a review of studies focused on AG and discuss pitfalls, which could bias the results. Current clinical applications as well as perspectives of future antiangiogenic treatment are also discussed.

Sensitivity and specificity of the fine needle aspiration biopsy of the thyroid: clinical point of view

INTRODUCTION

The rates of sensitivity and specificity of fine needle aspiration biopsy (FNAB) for the diagnosis of thyroid malignancy differ considerably among various reported series. These values are influenced by three factors: (a) whether only clearly positive and negative results are considered, or whether the commonly encountered 10-20% of indeterminate/suspicious ones are included; (b) whether adenomas are considered as neoplasms in one group with carcinomas; and (c) whether only histologically proven cases are used in calculations or whether patients with benign clinical follow-up are included.

AIM

The aim of the study was to evaluate the sensitivity and specificity of FNABs performed at this institution in the last 7 years from the clinical point of view, considering only benign vs. suspicious/malignant FNAB results (indicating surgery), and benign (including adenomas) vs. malignant definitive histology.

STUDY DESIGN

Retrospective study comparing pre-operative FNAB results with definitive histological examination after operation.

PATIENTS

A total of 2492 FNABs were performed in 2100 patients (1875 women and 225 men); their ages ranged from 9 to 85 years, with a median of 46 years. Clinical diagnosis was multinodular goitre in 1330, single nodule in 591, Hashimoto's thyroiditis in 147 and subacute thyroiditis in 32 cases. In 148 instances, the nodule was cystic. A history of previous treatment for carcinoma of the thyroid was present in 12 patients. Five hundred and thirty-six patients subsequently underwent thyroid surgery.

STATISTICS

The values of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were calculated.

RESULTS

The sensitivity was 86%, specificity 74%, PPV 34%, NPV 97% and diagnostic accuracy 75%.

CONCLUSIONS

The specificity and positive predictive value are low when fine needle aspiration biopsy results are divided into two categories only (these being indication for surgery or not), and when only suspicious/malignant fine needle aspiration biopsies with subsequent malignant histology are considered to be true positive. Nevertheless, the ability to discriminate 11.7% of patients with a 34% probability of malignancy (suspicious/malignant cytology) from 81.2% of patients (benign cytology) with a probability of only 3% is very helpful.

[Malignant myoepithelioma of the parotid gland: cytologic and histologic features]

A case of malignant myoepithelioma of the parotid gland in a 34-year-old female is presented. In the fine-needle aspiration material, there was predominance of poorly cohesive polygonal cells with marked nuclear pleomorphism; no mitotic figures were observed. Focally, fragments of myxoid metachromatic intercellular material were also present. Histologically, the tumor was encepsulated, showing focal invasion of the capsule and tumor thrombi in the capsular vessels. The tumor was predominantly solid and myxoid, composed of cells with epithelioid features, marked anisonucleosis and a low mitotic activity. Immunohistochemically, the cells revealed positive staining for S-100 protein, vimentin, cytokeratins, glial acidic fibrillary protein and carcinoembryonic antigen; only several cell groups expressed smooth muscle actin and desmin; muscle specific actin was uniformly negative. In differential diagnosis, it was important to distinguish malignant myoepitelioma mainly from pleomorphic adenoma (mixed tumor), benign myoepithelioma, carcinoma ex pleomorphic adenoma and malignant melanoma. The criteria of malignancy in myoepithelial tumors are discussed.

Epithelial-myoepithelial carcinoma of the bronchus

An extremely rare case of epithelial-myoepithelial carcinoma (EMC) of a lobar bronchus in a 47-year-old female is reported. Grossly, the tumor formed a polypoid mass obstructing the bronchial lumen. Microscopically, it was composed of two cellular types--epithelial cells with eosinophilic cytoplasm and clear myoepithelial cells. Numerous tubules formed by an inner epithelial and outer myoepithelial layer were found. Focally, the tumor showed solid growth of clear cells. Prominent hyalinization of the stroma was found. The nature of the cells was confirmed by positive expression of cytokeratins and epithelial membrane antigen in epithelial cells and vimentin and smooth muscle actin in myoepithelial cells. Differential diagnosis of EMC includes a broad spectrum of salivary gland-type tumors. Furthermore, metastases of clear cell carcinoma of the kidney or thyroid, clear cell ("sugar") tumor of the lung, glandular form of carcinoid, bronchioalveolar adenocarcinoma with myoepithelial cells and pulmonary adenosquamous carcinoma with amyloid-like stroma must be distinguished from EMC. The tumor has neither recurred nor metastasised, a fact supporting the current opinion, that EMC is a tumor of low grade malignancy.

[Pseudoangiomatous hyperplasia of mammary stroma]

Four cases of pseudoangiomatous hyperplasia of mammary stroma (PAH) were described (3 women and 1 man aged 15 to 42 years). Clinically in women, they presented as firm, nontender, movable nodules, 1 to 4 cm in diameter, diagnosed clinically usually as fibroadenoma. In the male patient, the lesion was tender, resembling gynecomastia. Microscopically, they were characterized by the presence of anastomosing, empty-looking, slit-shaped spaces irregularly lined by the spindle cells with small, uniformly ovoid nuclei, dispersed throughout the mammary stroma. Immunohistochemically, these cells were vimentin positive, factor VIII and CD31 negative. They did not express estrogen receptor, in one case there was a weak progesteron receptor positivity. Ultrastructurally, the lining cells were of a fibroblastic character. The pathogenesis of PAH is unclear, presumed to be of reactive nature by the authors, probably as an exuberant reaction of stromal cells to hormonal stimuli. In differential diagnosis, PAH should be distinguished from low-grade angiosarcoma, as well as from perilobular hemangioma, diffuse angiomatosis and vascular anomalies.