[Gastric metastases with a choriocarcinoma component from a postpuberal teratoma with mature histology]. / Metástasis gástricas con componente de coriocarcinoma de un teratoma testicular pospuberal con histología madura.

Germ cell tumors are the most frequent neoplasia in young males. The aims of this study is to describe a case in which a postpuberal teratoma suffers a transformation to choriocarcinoma and metastasize to stomach. We have made a systematic review in PubMed and consensus documents to study this mismatch between the tumour, metastasis and the exception of gastric metastatic affectation. We describe three options to explain this discordance: a mixed germ cells tumour, a burned out tumour or a germ cells tumour derived from a malignant germ cell tumour precursor or different clonal strains. After made a thorough investigation we conclude that the most truly option is the last one as we extensive explain below. Once the gastric metastatic lesions are extremely rare and reach to <5%, but there are not conclusive assessments.

Ectopic liver in a five-week-old embryo.

The first case of a placental tumor composed of benign hepatic tissue was published in 1986 and considered a placental benign hepatocellular adenoma. Since then, this lesion is better known as ectopic liver, and a total of 12 cases have been published. The ectopic liver located in the umbilical cord is an even rarer alteration, with only nine cases described to date. We report another case of ectopic liver, this time in an embryo of only five weeks of gestational age.

[Renal angioleiomyoma with a myogenic and melanocytic immunophenotype, as a variant of angiomyolipoma]. / Angioleiomioma renal con patrón inmunohistoquímico miogénico y melanocítico como variante del angiomiolipoma.

We present a case of a 67 year old male with a cortical nodular tumour of the left kidney. During a year's follow-up with ultrasound and MRI, the tumour was seen to increase in size by 16-20 mm. The nodule was surgically removed. Microscopically it was well defined and unencapsulated, with a proliferation of typical fusiform cells of smooth muscle cell appearance, clumped around well vascularized areas. Immunohistochemically, the neoplasm was positive for muscle markers (smooth muscle actin, desmin and caldesmon) and melanocyte markers (HMB-45 and Melan A). Our case would appear to be a renal neoplasm with an angioleiomyomatous pattern, but with immunohistochemical characteristics of angiomyolipoma (PEComa), however, without either a lipomatous or lipid cell component. We found no previous reports of this type of tumour in the literature.

Nasal embryonal rhabdomyosarcoma with bone marrow metastasis simulating acute leukemia: A case report and review of the literature.

We present a case of a nasal rhabdomyosarcoma (RMS) in a 27-year-old male with epistaxis and nasal obstruction due to a mass, which was subjected to prophylactic tumor embolization. However, histopathological study on the nasal biopsy was impossible due to necrotic changes. As blast cells were present in peripheral blood samples, a bone marrow biopsy was recommended in order to reach a definitive diagnosis. The possibility of an RMS in cases of bone marrow infiltration by a diffuse tumor constituted by small, round, blast-like cells mimicking acute leukemia should be assessed. Immunohistochemical staining in bone marrow biopsy and flow cytometry in aspirate samples may help to establish the diagnosis (CD45 negativity and CD56 positivity) and cytogenetic studies can be useful in identifying a RMS subtype. When clinically possible, it is desirable to await the results of the tumor immunophenotype and those of the primary mass or bone marrow biopsy to avoid possible errors of diagnosis and treatment.

Extraparenchymal ovarian and testicular Leydig cells: ectopic/heterotopic or orthotopic?

PURPOSE: We are conducting a prospective study trying to determine, in both sexes, the frequency of appearance of ectopic Leydig cells, their preferred location, their relationship with nerve structures and the possible causes of their appearance. METHODS: We have studied 86 cases that were removed according to different clinical indications for pathological study: uterine leyomiomas (n = 12), ovarian cystadenoma (n = 4), endometrial hyperplasia (n = 8), endometrial carcinoma (n = 12), cervical carcinoma (n = 4), seminoma (n = 4), fallopian tube ligatures (n = 24), vasectomies (n = 8), nonspecific orchiepididymitis (n = 2), and unknown (n = 8). RESULTS: We have observed ectopic Leydig cells in 13/86 cases (15.11%), 9/72 in the female samples (12.50%) and 4/14 in male samples (28.57%). The most frequent location was the mesosalpinx (4 of 13: 30.76%). CONCLUSIONS: These high figures lead us to believe that the ectopia of Leydig cells is not really a pathologic entity, but a finding related to specific functions yet to be determined.

Synovial tumefactive extramedullary hematopoiesis associated to polycythemia vera.

The case of a 66-year-old male patient with a chronic myeloproliferative type polycythemia vera disorder, who after 2 years of evolution is developing a tumefactive extramedullary hematopoiesis (TEH) located in the synovial of the articulation in the right knee, is described. The tumor histologically consists of a relatively lax and edematous synovial structure diffusely infiltrated by mature and semimature hematopoietic cellular population. The simultaneous study of the bone marrow reveals medullar spaces full of hematopoietic cellularity, with a predominance of megakaryocytic and red series, and with the addition of severe reticulin fibrosis, facts that suggest a progression toward myelofibrosis. The TEH developed in tissues without a reticulum endothelial system is very uncommon. We provide data about the first case located in the synovial membrane and we review the literature regarding this pathologic entity.