[Neuroendocrine tumor associated with an intestinal cyst: a case report]. / Tumor neuroendocrino asociado con quiste intestinal: presentación de un caso.

Intestinal (tailgut) cysts or retrorectal cystic hamartomas are rare benign lesions that are included in the category of developmental cystic lesions. Their origin is still uncertain, although several hypotheses have been proposed to explain their development. They are located mainly in the presacral (retrorectal) space and predominately affect middle-aged women (40-60 years). Taking into account location and histological characteristics, the main differential diagnoses include epidermoid cysts, duplication cysts and teratomas. Malignant transformation of these lesions is rare and preferentially into adenocarcinoma and neuroendocrine tumors. We present a case of an intestinal cyst associated with a well-differentiated neuroendocrine tumor (G1) in a 63-year-old woman.

[Cystic tubulopapillary adenoma with apocrine differentiation and BRAF V600E mutation. A case report and review of the literature]. / Adenoma tubulopapilar quístico con diferenciación apocrina: descripción de un caso con mutación de BRAF V600E y revisión de la literatura.

Syringocystadenoma papilliferum (SCAP), tubular adenoma (TA) and hydrocystoma (HC) are benign adnexal tumors. Recently it has been suggested that these lesions belong to the same morphological spectrum: Tubulopapillary cystic adenoma with apocrine differentiation (TPCAa). BRAF and K-Ras (KRAS) mutations have been described in SCAP and TA, but not in HC. Moreover, verrucous epithelial proliferations have been observed in TPCAa. We present a case of TPCAa with BRAF V600E mutation and BRAF VE1 immunohistochemical expression in the SCAP, AT, HC and verrucous hyperplasia components.

[Hereditary leiomyomatosis syndrome associated with renal cell carcinoma. A case report]. / Síndrome de leiomiomatosis hereditaria asociado a carcinoma de células renales. Presentación de un caso.

Hereditary leiomyomatosis (HL) is a rare autosomal dominant syndrome resulting from a mutation in the germline of the fumarate hydratase (FH) gene. Patients with this syndrome have an increased risk of cutaneous and uterine smooth muscle tumors as well as renal cancer. Renal carcinoma associated with hereditary leiomyomatosis (HLRCC) was recognized as a subtype of independent renal tumor in the 2016 WHO classification. We present a case of HLRCC occurring in a 39-year-old man with no family history or specific skin manifestations at the time of diagnosis.

[TFEB-amplified renal cell carcinoma. A case report and review of the literature]. / Carcinoma de células renales asociado a amplificación del gen TFEB. Presentación de un caso y revisión de la literatura.

Renal carcinomas associated with translocation of transcription factors of the MiT/TFE family include, according to the latest World Health Organization classification, carcinomas with Xp11 translocation that involve the TFE3 gene and those with translocation t(6;11)(p21;q12) that affect the TFEB gene. Each one of these sub-types have well-defined clinicopathological and molecular characteristics. Currently, progress in molecular techniques has led to the description of neoplasms with molecular changes in these same genes but with alterations different to translocation. Thus, recently, cases have been published of TFEB-amplified renal carcinomas with prognoses that vary from cases associated with translocation and could therefore represent a new entity. We present a case of TFEB-amplified renal carcinoma with a full description of the clinicopathological characteristics and an updated revision of these neoplasms.

[Pseudomyogenic hemangioendothelioma in the upper limb: A case report and literature review]. / Hemangioendotelioma pseudomiogénico en miembro superior: descripción de un caso y revisión de la literatura.

Pseudomyogenic hemangioendothelioma, also called epithelioid sarcoma-like hemangioendothelioma, is a rare, vascular neoplasm usually with indolent behaviour. It was introduced in the latest World Health Organization (WHO) Classification of Tumours of Soft Tissue. We report a case of a 45 year-old patient presenting with a localized, palpable and slightly painful lesion in the left arm. Histologically it consisted of fascicles of spindle and epithelioid cells with ample eosinophilic cytoplasm, without nuclear pleomorphism or significant mitotic activity. Tumour cells showed diffuse expression for cytokeratin AE1/AE3, CD31 and FLI1, intact expression for INI1 and negativity for CD34. We describe the clinical, histological, molecular and immunohistochemical features of pseudomyogenic hemangioendothelioma and review the pertinent literature.

Toxic epidermal necrolysis in polymedicated patient treated with radiotherapy.

Temozolomide is an oral alkylating agent indicated for the treatment of patients with glioblastoma multiforme concomitantly with radiotherapy and subsequently as monotherapy treatment. We report the case of a patient who developed toxic epidermal necrolysis (TEN) while she was being treated with chemoradiotherapy and several drugs. Cutaneous tests were performed with the drugs involved with negative result. Although the occurrence of TEN contraindicates suspected drug readministration, we based the decision to perform the controlled administration of temozolomide on the following reasons: (1) the poor prognosis of the underlying disease, (2) the lack of therapeutic alternatives, (3) the suspicion that other drugs taken by the patient simultaneously may be responsible (as anticonvulsants and trimethoprim sulfamethoxazole [TMP-SMX]), and (4) temozolomide was the first choice for treating the patient's disease. The administration of a cumulative dose of 60 mg of temozolomide caused a slight skin reaction. Given this result, we conducted controlled administration of other drugs involved. Dexamethasone, codeine, omeprazole and levetiracetam were well tolerated. However, TMP-SMX produced a similar reaction to that caused by temozolomide. In conclusion, we present the first case of TEN induced by temozolomide and TMP-SMX associated with cranial radiotherapy confirmed by controlled administration. Radiotherapy in combination with these drugs could have favored TEN, as some authors have postulated, but we cannot prove this.

Gastrointestinal stromal tumors: morphological, immunohistochemical and molecular changes associated with kinase inhibitor therapy.

Recurrent or metastatic GISTs are currently treated with kinase inhibitors since they achieves disease control in 70-85% of patients but this response depend on KIT and PDGFRA gene mutation status. We review the morfological and molecular findings associated to kinase inhibitors administration in GISTs based on the literature on Medline and authors' own experience. The initial response to kinase inhibitors (imatinib mesylate, Gleevec, Novartis) usually is partial and depend on the mutational KIT or PDGFRA state. Amongst patients wih KIT mutations, the best results are achived in those harboring exon 11 (85%) and exon 9 (45%) mutations. GISTs harboring PDGFRA gene mutations generally respond favorably except those involving the Asp842Val mutation. In the absence of KIT/PDGFRA gene mutations, partial response or disease stabilization is reported in 23% and 50% of patients, respectively, and disease progression in 19%. Histological examination of tumors displaying an initial response to imatinib reveals a highly-variable reduction in the number of tumor cells, a decline in the proliferative index, myxohyaline or sclerohyaline stroma, and a varying degree of bleeding and edema, necrosis and cystification. 72% of patients with initial good response to imatinib, display metastases or new nodule growth within an existing clinically-quiescent tumor after 12-36 months of treatment. This secondary resistance is characterized by a number of well-defined morphological and molecular changes. Histologically, the new growths display increased mitotic activity, pleomorphism, an epithelioid or mixed phenotype and persistent KIT expression although more rarely, dedifferentiation and loss of KIT expression (Fig. 4), as well as trans-differentiation into a rhabdomyosarcoma or epithelial phenotype has been reported. Molecularly, 46-67% of patients present additional KIT mutations, generally in the kinase domain (exons 13, 14 and 17) but also in the ATP-binding domain (exons 15,16) of the same allele. Secondary PDGFRA mutations are very rare. Secondary mutations have not been observed in GISTs not harboring KIT/PDGFRA mutations, or in tumors displaying an unusual morphology or loss of CD117 expression. A number of studies highlight the presence of different resistance mutations within different new tumor nodules, as well as the simultaneous development of distinct resistant tumor subclones within a single lesion (acquired polyclonal resistance). Secondary mutation in genes other than KIT/PDGFRA has only been reported in BRAF (Val600Glu).

Primary testicular lymphoma with extranodal involvement.

We report the case of a 65-year-old man who presented with a right testicular mass and synchronous involvement of skin and Waldeyer's ring. These facts led us to the working diagnosis of malignant primary testicular lymphoma. MATERIAL/RESULTS: We present the case with comments and make a bibliographic review of the disease. CONCLUSIONS: Primary testicular lymphoma is an uncommon testicular tumour that accounts for not more that 9% of all testicular tumours in the series with higher incidence. Testicular lymphomas are also rare among haematopoietic tumours, accounting for just 1% of all lymphomas, but due to their highly malignant histopathology they may become highly aggressive tumours. Patient age at presentation is over 60 years which makes it the most frequent tumour for this age group. 70% of recently diagnosed patients show Ann Arbor stages I and II. Tumours in advanced-stage have a predilection for spreading to extranodal sites such as central nervous system, skin, Waldeyer's ring and lungs.

[Testicular choriocarcinoma with pure histological pattern. Necropsy study in a representative case]. / Coriocarcinoma testicular con patron histologico puro. Estudio necropsico de un caso representativo.

OBJECTIVE: Pure testicular choriocarcinoma is a relatively infrequent neoplasia with an ominous prognosis. METHODS: We report the necropsy study of a 21-year old male patient with generalized metastases of a primary pure testicular choriocarcinoma. RESULTS: The aggressiveness of this neoplasia is demonstrated by extensive tumor dissemination in early stages, in which testicular clinical manifestations are often absent. CONCLUSIONS: In front of any choriocarcinoma it is imperative to perform an extensive sampling of the lesion with the aim to detect possible foci of germ cell neoplasia which constitute a mixed pattern.