On the bright side of market concentration in a mixed-oligopoly healthcare industry.

We describe the healthcare industry as a mixed oligopoly, where a public and two private providers compete, and examine the effects of a merger between the two private healthcare providers on prices, quality, and welfare. When the price and (eventually) quality of the public provider are regulated, the cost synergies required for the merger to increase consumer welfare are less significant than in a setting with only profit-maximizing providers. When, instead, the public provider can adjust its policy to the rivals' behavior and maximizes a weighted sum of profits and consumer surplus (i.e., it has 'semi-altruistic' preferences), the merger is consumer surplus increasing if the public provider is sufficiently altruist, in some cases even absent efficiencies. These results suggest that ignoring the role and objectives of the public sector in the healthcare industry may lead agencies to reject mergers that, while would decrease consumer welfare in fully privatized industries, would increase it in mixed oligopolies.

Desmoplastic Small Round Cell Tumor of the Kidney: Report of a Case, Literature Review, and Comprehensive Discussion of the Distinctive Morphologic, Immunohistochemical, and Molecular Features in the Differential Diagnosis of Small Round Cell Tumors Affecting the Kidney.

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive neoplasm typically presenting with widespread involvement of the abdominopelvic peritoneum of adolescent males, usually without organ-based primary. Although it is believed to originate from the serous (mainly peritoneal) membranes, intracranial, sinonasal, intraosseous, and other soft tissue sites are also documented. A chromosomal translocation t(11:22)(p13;q12) signature that fuses EWSR1 and WT1 genes results in the production of a chimeric protein with transcriptional regulatory activity that drives oncogenesis. Integration of clinical, morphologic, immunohistochemical, and genetic data is necessary to arrive at the correct diagnosis, especially when the tumor arises in an atypical site. A 15-year-old male presented with hematuria and was found to have a large renal tumor associated with adrenal, liver, lung, and bone metastases. Histopathologic and immunophenotypic features were distinctive for DSRCT. This diagnosis was confirmed by means of fluorescence in situ hybridization and cytogenetic analysis, which documented the pathognomonic t(11;22) translocation, and by reverse transcription polymerase chain reaction on snap-frozen tissue, which revealed the EWSR1/WT1-specific chimeric transcript. Despite high-dose chemotherapy and radiation therapy targeted to a single T11 vertebral metastasis, the disease progressed, and the patient died 4 years after the diagnosis. A search of electronic databases for DSRCT yielded 16 cases of well-documented renal primaries out of around 1570 cases from all sites gathered from the global literature. Desmoplastic small round blue cell tumor and other primary renal tumors considered in the differential diagnosis with DSRCT are discussed.

Metastatic Basal Cell Carcinoma of the Skin: A Comprehensive Literature Review, Including Advances in Molecular Therapeutics.

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. In Europe, the incidence of BCC ranges from 44.6 to 128 cases per 100,000 inhabitants annually, whereas in the United States, the yearly incidence rate ranges between 500 and 1500. The global incidence has been calculated to be as high as 10 million cases of BCC per year. There are 2 main clinical patterns of BCC-the familial BCC in basal cell nevus syndrome and sporadic BCC. The etiology of cutaneous BCC is usually the result of the interaction between solar ultraviolet radiation and genetic factors. Somatic or germline mutations in the effector components of the hedgehog signaling pathway (ie, PTCH1, PTCH2, SMO or SUFU genes) are responsible for ∼90% of the cases of both sporadic and familial BCC, all causing a constitutive activation of the hedgehog pathway. Cutaneous BCC very rarely metastasizes, and diagnosis in metastatic sites can be very difficult. Metastatic BCC has weakly effective therapeutic options with a poor prognosis until few years ago. In 2012, small-molecule therapies, involving inactivation of the hedgehog signaling pathway, and capable of reducing tumor growth and progression have been introduced into clinical practice for advanced (locally advanced or metastatic) BCC. We performed a comprehensive literature review on metastatic BCC and found at least 915 cases reported to date. In addition, we extensively discussed the differential diagnosis of metastatic BCC, and outlined the advances in clinical therapeutics involving these small molecules.

Metastatic Cutaneous Basal Cell Carcinoma: Report of 2 Cases Preceding the Hedgehog Pathway Antagonists Era.

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. However, metastatic BCC is a very rare event with weakly effective therapeutic options and a poor prognosis, until a few years ago. In 2012, small-molecule therapies, capable of inactivating the hedgehog signaling pathway and thus reducing tumor growth and progression, were introduced into clinical practice for the treatment of patients with advanced BCC. We present retrospectively 2 personal cases of metastatic BCC of the skin, from the premolecular therapy era, from primary tumors that arose years before in the head and neck area. The former case occurred in a 45-year-old woman with a history of recurrent BCC of the retroauricular skin who eventually died due to diffuse metastatic spread. The latter case concerned a 70-year-old man also with a history of recurrent BCC of the nasal-perinasal skin who developed multiple subcutaneous and lymph node metastases in the neck. In both cases, the diagnoses were based on biopsies of the metastatic sites. The first patient died 5 months after the diagnosis of metastatic disease, while the second was alive and disease-free 2 years after neck lymph node dissection and external radiation therapy, and then lost to follow-up. We extensively discuss several tumor entities with basal or basaloid features that may enter the differential diagnosis with BCC in metastatic sites. In addition, we briefly summarize the advances in clinical therapeutics using small molecules, which are now an integral part of the treatment of such advanced BCC cases.

Phosphaturic Mesenchymal Tumor of Soft Tissue of the Foot: Report of a Case With Review of the Literature.

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm that ectopically secretes fibroblast growth factor 23, a bone cell-derived protein that regulates phosphate homeostasis. The overproduction of fibroblast growth factor 23 causes a paraneoplastic syndrome characterized by hyperphosphaturia, hypophosphatemia, hypovitaminosis D, and vitamin D refractory rickets/osteomalacia, effects that disappear with tumor removal. The PMT may occur in several anatomic regions, mainly in the limbs, usually involving both soft tissue and bone. Acral locations occur in 10% to 15% of the cases, mostly in the feet, with 95 cases reported in this anatomic region to date. We report a case of a PMT in a young adult male who presented in 2007 with the classic constellation of signs and symptoms. A small soft-tissue tumor was detected in his right heel, 3 years after exhaustively seeking for it by various imaging techniques performed at different institutions. Before the tumor was detected, attempts to manage this patient's osteomalacia with phosphate and vitamin D (both calcitriol and ergocalciferol) supplementation were unsuccessful. Following surgical resection, the patient experienced prompt correction of the phosphaturia and gradual reconstitution of his bone mineralization. The pathologic diagnosis was (benign) PMT, mixed connective tissue type. In 2019, 12 years after resection, the patient is asymptomatic, and his bone mineral homeostasis has been restored.

Effects of KEAP1 Silencing on the Regulation of NRF2 Activity in Neuroendocrine Lung Tumors.

BACKGROUND: The KEAP1/NRF2 pathway has been widely investigated in tumors since it was implicated in cancer cells survival and therapies resistance. In lung tumors the deregulation of this pathway is mainly related to point mutations of KEAP1 and NFE2L2 genes and KEAP1 promoter hypermethylation, but these two genes have been rarely investigated in low/intermediate grade neuroendocrine tumors of the lung. METHODS: The effects of KEAP1 silencing on NRF2 activity was investigated in H720 and H727 carcinoid cell lines and results were compared with those obtained by molecular profiling of KEAP1 and NFE2L2 in a collection of 47 lung carcinoids. The correlation between methylation and transcript levels was assessed by 5-aza-dC treatment. RESULTS: We demonstrated that in carcinoid cell lines, the KEAP1 silencing induces an upregulation of NRF2 and some of its targets and that there is a direct correlation between KEAP1 methylation and its mRNA levels. A KEAP1 hypermethylation and Loss of Heterozygosity at KEAP1 gene locus was also observed in nearly half of lung carcinoids. CONCLUSIONS: This is the first study that has described the effects of KEAP1 silencing on the regulation of NRF2 activity in lung carcinoids cells. The epigenetic deregulation of the KEAP1/NRF2 by a KEAP1 promoter hypermethylation system appears to be a frequent event in lung carcinoids.

Anaplastic Kaposi's Sarcoma of the Adrenal in an HIV-negative Patient With Literature Review.

Kaposi's sarcoma (KS) is a peculiar tumor of viral etiology, with the HHV8 rhadinovirus playing a fundamental role in its development. Several epidemiological categories of KS have been identified, of which the sporadic, endemic, iatrogenic, and the epidemic are the main ones. Several histologic disease morphologies have been described, such as inflammatory, angiomatous, spindle cell, mixed, and the anaplastic (sarcomatous) subtypes. The skin of the limbs is most commonly affected, but any other organ or site may be involved. Microscopically KS may enter the differential diagnosis with several different entities, and for this purpose the immunohistochemical detection of the viral latent nuclear antigen-1 (LNA-1) may be crucial. Sporadic KS is usually benign, but rarely it may be aggressive. Anaplastic histology heralds an ominous course in any clinical context. We report a case of anaplastic retroperitoneal KS, occurring in an HIV-negative adult man. This patient presented with a huge left suprarenal mass, which was totally resected, and initially diagnosed as inflammatory leiomyosarcoma, because of the monomorphic spindle cell tumor morphology. After 12 years the tumor recurred locally as an unresectable mass, which was biopsied and examined. At the time of recurrence, the histologic slides of the primary tumor were reviewed, and the previous diagnosis was changed to that of atypical KS. Histologically the recurrent tumor showed both spindle cell and epithelioid appearances. Strongly diffuse HHV8/LAN-1 immunopositivity was documented in both tumors. The final diagnosis for the entire case was anaplastic KS. Then, the patient died in a few months.

Syringocystadenoma Papilliferum of the Anogenital Area and Buttocks: A Report of 16 Cases, Including Human Papillomavirus Analysis and HRAS and BRAF V600 Mutation Studies.

Syringocystadenoma papilliferum (SCAP) is a benign tumor most commonly located on the head and neck area often associated with nevus sebaceus. In its usual location, the human papillomavirus (HPV) DNA and mutations in the RAS/mitogen-activated protein kinase signaling pathway have been detected in SCAP. We studied 16 cases of SCAP in the anogenital areas and buttock where this neoplasm is rare and attempted to find out whether SCAP in these sites have different histopathological and molecular biological features. It seems that there is no significant difference between the morphology of anogenital SCAP and SCAP in other locations. Several tumors in our cohort demonstrated features resembling those seen in warts, but HPV DNA was not found in these lesions. On the contrary, we identified DNA of HPV high-risk types in some tumors without HPV-related morphology. Our study confirms the role of HRAS and BRAF V600 mutations in the pathogenesis of SCAP, including SCAP in the anogenital areas and buttock.

Regional regulators in health care service under quality competition: A game theoretical model.

In several countries, health care services are provided by public and/or private subjects, and they are reimbursed by the government, on the basis of regulated prices (in most countries, diagnosis-related group). Providers take prices as given and compete on quality to attract patients. In some countries, regulated prices differ across regions. This paper focuses on the interdependence between regional regulators within a country: It studies how price setters of different regions interact, in a simple but realistic framework. Specifically, we model a circular city as divided in two administrative regions. Each region has two providers and one regulator, who sets the local price. Patients are mobile and make their choice on the basis of provider location and service quality. Interregional mobility occurs in the presence of asymmetries in providers' cost efficiency, regulated prices, and service quality. We show that the optimal regulated price is higher in the region with the more efficient providers; we also show that decentralisation of price regulation implies higher expenditure but higher patients' welfare.

Extraneuraxial hemangioblastoma: A clinicopathologic study of 10 cases with molecular analysis of the VHL gene.

Less than 250 extraneuraxial hemangioblastomas occurring in paraneuraxial or peripheral sites have been reported to date, sporadically or in the setting of von Hippel-Lindau disease. Seventeen such cases underwent molecular genetic analysis, using either the patient's peripheral blood in 9 cases or paraffin embedded tumor tissue in the rest. VHL gene mutations were documented in 3/9 cases in which DNA from peripheral blood lymphocytes was used, all with clinically manifest von Hippel-Lindau disease; instead, no VHL gene alterations were found in all of the 8 cases with sporadic extraneuraxial hemangioblastoma in which DNA from tumor tissue was analyzed. Our aim is to investigate the molecular genetic profile of the VHL gene in extraneuraxial hemangioblastoma using paraffin embedded tumor tissues. The clinical features, histopathology, and molecular investigations of 10 extraneuraxial hemangioblastomas (7 females, 3 males; median age: 47 years) are presented herein. The histopathologic diagnosis was supported by immunohistochemistry (10/10) and electron microscopy (4/10). Molecular genetic analysis was conducted (10/10) for VHL gene mutations, LOH, and gene promoter methylation. Two of the present cases were already published with only limited or no molecular investigations. Four tumors of the present series were paraneuraxial, and 6 peripheral (2 involved soft tissues, and 4 the kidney). One tumor was von Hippel-Lindau disease-associated, 1 was classified as "hemangioblastoma-only VHLD", 7 were sporadic, and one was unknown. All were histopathologically analogous to their counterpart located inside the central nervous system. Immunophenotypically, all tumors expressed vimentin, S-100, NSE, and alpha-inhibin (10/10). Ultrastructurally, unbound lipid droplets filled the cytoplasms of the stromal cells. Molecular analysis revealed 3 inactivating mutations (1 germline, two somatic) in the coding sequence of the VHL gene in 2 different extraneuraxial hemangioblastomas, and LOH in 4 (two as a double hit), all non-renal extraneuraxial hemangioblastomas. Methylation analysis failed to disclose promoter methylation in any case. In conclusion, we report eight new cases from the wide category of extraneuraxial hemangioblastomas (4 paraneuraxial, and 4 renal), one of which was von Hippel-Lindau disease-associated and 7 sporadic. VHL gene alterations were found not only in the von Hippel-Lindau disease-associated tumor, but - for the first time - also in 3 sporadic ones, two of which with novel mutations.

Extraneuraxial Hemangioblastoma: Clinicopathologic Features and Review of the Literature.

Extraneuraxial hemangioblastoma occurs in nervous paraneuraxial structures, somatic tissues, and visceral organs, as part of von Hippel-Lindau disease (VHLD) or in sporadic cases. The VHL gene plausibly plays a key role in the initiation and tumorigenesis of both central nervous system and extraneuraxial hemangioblastoma, therefore, the underlying molecular and genetic mechanisms of the tumor growth are initially reviewed. The clinical criteria for the diagnosis of VHLD are summarized, with emphasis on the distinction of sporadic hemangioblastoma from the form fruste of VHLD (eg, hemangioblastoma-only VHLD). The world literature on the topic of extraneuraxial hemangioblastomas has been comprehensively reviewed with ∼200 cases reported to date: up to 140 paraneuraxial, mostly of proximal spinal nerve roots, and 65 peripheral, 15 of soft tissue, 6 peripheral nerve, 5 bone, and 39 of internal viscera, including 26 renal and 13 nonrenal. A handful of possible yet uncertain cases from older literature are not included in this review. The clinicopathologic features of extraneuraxial hemangioblastoma are selectively presented by anatomic site of origin, and the differential diagnosis is emphasized in these subsets. Reference is made also to 10 of the authors' personal cases of extraneuraxial hemangioblastomas, which include 4 paraneuraxial and 6 peripheral (2 soft tissue hemangioblastoma and 4 renal).

Hidradenoma Papilliferum: A Clinicopathologic Study of 264 Tumors From 261 Patients, With Emphasis on Mammary-Type Alterations.

Hidradenoma papilliferum (HP), also known as papillary hidradenoma, is the most common benign lesion of the female anogenital area derived from anogenital mammary-like glands (AGMLG). HP can be viewed conceptually as the cutaneous counterpart of mammary intraductal papilloma. The authors have studied 264 cases of HP, detailing various changes in the tumor and adjacent AGMLG, with emphasis on mammary-type alterations. In many HP, the authors noticed changes typical for benign breast lesions, such as sclerosing adenosis-like changes, usual, and atypical ductal hyperplasia. Almost in a third of cases, remnants of AGMLG adjacent to the lesion were evident, manifesting columnar changes reminiscent of those seen in breast lesions. This study shows that the histopathological changes in HP run a broad spectrum comparable with that in the mammary counterpart and benign breast disease.

BRAF V600E and risk stratification of thyroid microcarcinoma: a multicenter pathological and clinical study.

Studies from single institutions have analyzed BRAF in papillary microcarcinomas, sometimes with contradictory results. Most of them have provided limited integration of histological and clinical data. To obtain a comprehensive picture of BRAF V600E-mutated microcarcinomas and to evaluate the role of BRAF testing in risk stratification we performed a retrospective multicenter analysis integrating microscopical, pathological, and clinical information. Three hundred and sixty-five samples from 300 patients treated at six medical institutions covering different geographical regions of Italy were analyzed with central review of all cases. BRAF V600E statistical analysis was conducted on 298 microcarcinomas from 264 patients after exclusion of those that did not meet the required criteria. BRAF V600E was identified in 145/298 tumors (49%) including the following subtypes: 35/37 (95%, P<0.0001) tall cell and 72/114 (64%, P<0.0001) classic; conversely 94/129 follicular variant papillary microcarcinomas (73%, P<0.0001) were BRAF wild type. BRAF V600E-mutated microcarcinomas were characterized by markedly infiltrative contours (P<0.0001) with elongated strings of neoplastic cells departing from the tumor, and by intraglandular tumor spread (P<0.0001), typically within 5 mm of the tumor border. Multivariate analysis correlated BRAF V600E with specific microscopic features (nuclear grooves, optically clear nuclei, tall cells within the tumor, and tumor fibrosis), aggressive growth pattern (infiltrative tumor border, extension into extrathyroidal tissues, and intraglandular tumor spread), higher American Thyroid Association recurrence risk group, and non-incidental tumor discovery. The following showed the strongest link to BRAF V600E: tall cell subtype, many neoplastic cells with nuclear grooves or with optically clear nuclei, infiltrative growth, intraglandular tumor spread, and a tumor discovery that was non-incidental. BRAF V600E-mutated microcarcinomas represent a distinct biological subtype. The mutation is associated with conventional clinico-pathological features considered to be adverse prognostic factors for papillary microcarcinoma, for which it could be regarded as a surrogate marker. BRAF analysis may be useful to identify tumors (BRAF wild type) that have negligible clinical risk.

Selected case from the Arkadi M. Rywlin International Pathology Slide Club: carcinoma of the transverse colon in a young girl.

We report a case of a 14-year-old female with primary adenocarcinoma of the transverse colon. She was hospitalized after presenting with abdominal pain and signs of intestinal obstruction. There was no health antecedent or family history of neoplasia. Physical examination revealed a distended abdomen. Tenderness was elicited to palpation of the right lower quadrant. Magnetic resonance imaging of the abdomen revealed obstructive signs, with a constricting lesion in the mid-transverse colon of probable neoplastic nature. Laparoscopic segmental resection of the colon was followed by standard right hemicolectomy. A circumferential mid-transverse tumor was diagnosed as primary colorectal carcinoma (CRC) of signet-ring cell type, AJCC stage IIIC, Dukes' C stage. On the basis of immunohistochemistry and clinical data, hereditary nonpolyposis and hamartomatous colorectal cancer syndromes were excluded. Involvement of either the p53, BRAF, or K-RAS genes was ruled out by immunohistochemistry profiling and genetic testing. The neoplasm was categorized as sporadic. The possibility of activation of the Wnt signaling pathway was suspected, because of a defective turnover of the ß-catenin protein. Postoperatively, the patient was treated with both systemic and intra-abdominal adjuvant chemotherapy, including oxaliplatin. Between 18 and 24 months after diagnosis, intra-abdominal tumor recurrences were detected. The patient underwent bilateral oophorectomies for Krukenberg tumors and received salvage chemotherapy. Recently, additional recurrent metastatic retroperitoneal disease caused hydronephrosis. The retroperitoneal mass was debulked and a ureteric stent was placed. At the time of this writing, 43 months after diagnosis, the patient is receiving FOLFOX chemotherapy combined with panitumumab. CRC of childhood is exceedingly rare, generally develops in the setting of unrecognized genetic predisposing factors to cancer, presents with advanced disease, is high grade, and tends to have dismal prognosis.

Oncofetal expression of Wilms' tumor 1 (WT1) protein in human fetal, adult and neoplastic skeletal muscle tissues.

There is increasing evidence that WT1 protein expression is found not only at nuclear, but also at cytoplasmic, level in several developing and neoplastic tissues. In order to better understand the possible role of WT1 protein in human skeletal myogenesis and oncogenesis of rhabdomyosarcoma, we assessed immunohistochemically its comparative expression in a large series of human developing, adult and neoplastic skeletal muscle tissues. The present study shows that WT1 protein is developmentally expressed in the cytoplasm of human myoblasts from the 6 weeks of gestational age. This expression was maintained in the myotubes of developing muscles of the trunk, head, neck, and extremities, while it was down-regulated in fetal skeletal fibers from 20 weeks of gestational age as well as in adult normal skeletal muscle. Notably, WT1 immunostaining disappeared from rhabdomyomas, whereas it was strongly and diffusely re-expressed in all cases (27/27) of embryonal and alveolar rhabdomyosarcoma. The comparative evaluation of the immunohistochemical findings revealed that WT1 cytoplasmic expression in rhabdomyosarcoma may represent an ontogenetic reversal, and this nuclear transcription factor can also be considered an oncofetal protein which can be exploitable as an additional, highly sensitive immunomarker, together with desmin, myogenin and MyoD1, of this tumor. Moreover, our observations support the rationale for the use of WT1 protein-based target therapy in high risk rhabdomyosarcomas in children and adolescents.

Selected case from the Arkadi M. Rywlin International Pathology Slide Series: Asymmetric, segmental glomerulocystic kidney in an infant with tuberous sclerosis complex.

A Hispanic newborn male, the product of nonconsanguineous parents, exhibited major and minor signs of tuberous sclerosis complex (TSC). MRI of the abdomen disclosed a discrete unilateral, cystic, right upper pole renal mass that prompted a nephrectomy. Histologic examination showed a polycystic renal mass that involved all segments of the nephron, with a preponderantly glomerulocystic pattern. The cysts were rounded, uniform, and small, most measuring 2 to 3 mm in diameter. The lining of the cysts was hyperplastic, made up of tall epithelial cells with eosinophilic granular cytoplasm and large nuclei, and focally formed mounds and papillary tufts. DNA analysis detected a constitutional deletion of exon 1 in the TSC2 gene on chromosome 16p13.3. Cystogenesis in TSC2 is manifested because of alteration or dysfunction of the primary cilium, where polycystin, the gene product of PKD1 gene, is localized. Renal cysts are often seen in TSC, varying in number from a few to innumerable, involving all segments of the nephron, including Bowman spaces, and are currently considered as one of the minor diagnostic features. A glomerulocystic pattern is a rare form of kidney involvement in TSC that aptly describes the innumerable cystically dilated Bowman spaces. Glomerulocystic kidney associated with the aforementioned hyperplastic epithelial lining (TSC epithelium) is sufficiently characteristic that could conceivably serve as a major TSC feature in the future.

Selected case from the Arkadi M. Rywlin international pathology slide series: diffuse dendriform pulmonary ossification: report of 2 cases with review of the literature.

Two cases of diffuse dendriform pulmonary ossification (DPO) are presented, one of the secondary type and the other of the idiopathic type. Case 1 was an adult female patient who underwent thoracic surgery to remove a posterior mediastinal bronchogenic cyst, which was discovered on a computed tomography scan performed after an episode of pneumonia when traction bronchiectasis with interstitial lung disease/fibrosis was also suspected in the lungs. Histologic examination performed on the resected lung tissue revealed numerous scattered small osseous spicules on a background of intense interstitial inflammation and fibrosis, leading to further clinical and laboratory investigations and the final diagnosis of DPO secondary to lung involvement by scleroderma. Case 2 was an adult male patient who underwent thoracoscopic exploration after a computed tomography scan, which revealed traction bronchiectasis with linear thickening of the interstitial lung tissue. Histologic examination of the lung tissue specimen revealed numerous osseous spicules in the absence of interstitial septal inflammation. Noteworthy in this case were also some nodules of collagenized tissue similar to those seen in the lungs of patients affected by Ehlers-Danlos syndrome. The absence of any clinical sign or symptoms related to Ehlers-Danlos syndrome attest to the nonspecificity of these pulmonary fibrous nodules. No case of DPO secondary to scleroderma has been reported in the literature so far, although around half of the patients with scleroderma manifest pulmonary diseases. Idiopathic DPO is even rarer, usually discovered postmortem, with only 20 cases diagnosed in life with lung biopsies taken by open surgery or through a thoracoscopic approach. DPO is often misdiagnosed radiologically as bronchiectasis and/or interstitial lung disease/fibrosis.

Selected case from the Arkadi M. Rywlin International Pathology Slide Series: Mitochondrial myopathy presenting with chronic progressive external ophthalmoplegia (CPEO): a case report.

A 43-year-old female patient diagnosed with chronic progressive external ophthalmoplegia (CPEO) because of mitochondrial myopathy documented by muscle biopsy is presented. The chief complaints were represented by blepharoptosis and ophthalmoplegia. The muscle biopsy was evaluated by histology, using the appropriate histochemical and histoenzimological stains. Ragged red fibers with Gomori trichrome stain were seen, which showed cytochrome c oxydase deficiency and abnormal succinate dehydrogenase staining in around 20% of muscle fibres. Electron microscopy was also performed which demonstrated abnormal, hyperplastic, pleomorphic, and hypertrophic mitochondria, characterized by paracrystalline inclusions arranged in parallel rows ("parking-lot" inclusions), consisting of rectangular arrays of mitochondrial membranes in a linear or grid-like pattern. In conclusion, mitochondrial myopathy was definitely diagnosed. Although molecular analysis, which was subsequently carried out, failed to reveal mutations in the mitochondrial DNA or in selected nuclear genes, the pathologic diagnosis was not changed. The differential diagnosis of CPEO with other forms of ocular myopathies as well as the possible association of CPEO with systemic syndromes is discussed. Ophtalmologists and medical internists should always suspect CPEO when dealing with patients affected by ocular myopathy, either in its pure form or in association with other myopathic or systemic signs.

Selected case from the Arkadi M. Rywlin international pathology slide series: lymphangiomatosis of the spleen associated with ipsilateral abdominopelvic and lower extremity venolymphatic malformations: a case report and review of the literature.

Herein, we report a 26-year-old patient with lymphangiomatosis of the spleen associated with multiple lymphatic and venous malformations. This patient underwent excision of a large lymphatic malformation of the left abdominal wall during childhood. A venous malformation of her left lower limb was excised during adolescence. Additional lymphatic malformations were found in the soft tissue of her left thigh at the age of 20. During hospitalization for a huge vulvar hemangioma at the age of 26, she was incidentally found to have asymptomatic splenomegaly, for which she underwent splenectomy. Examination of the spleen revealed diffuse involvement by a lymphatic anomaly predominantly forming small cystic spaces. Lymphangiomatosis of the spleen is rare and is classically separated into an isolated or pure form and a generalized form when it is associated with involvement of other viscera and/or multiple soft-tissue planes. This patient was affected by a borderline form of splenic lymphangiomatosis with limited somatic involvement of the superficial soft tissues and blood vessels. Notably, all the additional vascular malformations in this patient were left sided, and at this time there was no additional involvement of internal organ. No hereditary or known syndrome was identified.

Selected case from the Arkadi M. Rywlin International Pathology Slide Series: Leiomyomatosis peritonealis disseminata: report of 3 cases with extensive review of the literature.

We present the clinicopathologic features of 3 cases of leiomyomatosis peritonealis disseminata (LPD). The patients were 33, 34, and 41 years old at the time of diagnoses. The 3 women had undergone laparoscopic removal of multiple uterine leiomyomas between 1 and 6 years before the diagnoses of LPD. Laparoscopic uterine leiomyomectomies were performed on 3 occasions in patient 1, and once in patients 2 and 3 by the time a diagnosis of LPD was made. In patients 2 and 3, one of the multiple uterine leiomyomas had been qualified as mitotically active. Patients 1 and 2 received hormonal treatment before LPD was diagnosed. Malignancy was clinically and/or pathologically suspected in all the 3 cases. Patients 1 and 2 were managed conservatively. Patient 3 underwent radical hysterectomy with bilateral adnexectomy and omentectomy. Patients 1 and 2 belong to a rare subset of LPD that have fewer tumor nodules larger (5 to 10 cm) than typically seen. Patient 3 was classic in that she exhibited innumerable nodules measuring between a few millimeters and 1.5 cm, intraoperatively mimicking peritoneal carcinomatosis. Histopathologically, patients 1 and 2 were diagnosed as pure LPD, whereas patient 3 was diagnosed as LPD associated with endometriosis (adenomyosis type). Patients 1 and 3 had incipient foci of leiomyomatous changes in the blood vessel walls, at the site of the LPD tumors, supporting the hypothesis that these are de novo lesions arising locally and not migrated or disseminated from the previously excised or concurrent uterine smooth muscle tumors, usually seen in this context. Conceivably, laparoscopic leiomyomectomy with morcellation may play a role in the pathogenesis of this rare condition, at least in hormonally susceptible patients. Alternatively, LPD may derive from metaplastic submesothelial cells, a condition analogous to gliomatosis peritonei.