Glomerulocystic kidney presenting as a unilateral kidney mass in a newborn with tuberous sclerosis: Report of a case and review of the literature.

Glomerular cysts are defined as a 2-3 times dilation of Bowman spaces and their presence in at least 5% of the glomeruli defines the kidneys as glomerulocystic (GCK). The association between cystic kidney disease and the tuberous sclerosis complex (TSC) is well known, but its presentation as a unilateral mass with glomerulocystic pattern is rare. We describe a case of an infant with a prenatal diagnosis of TSC, with a renal mass that was believed to be a renal tumor. A four-month-old infant with maternal history of TSC and prenatally diagnosed subependymal nodules and a right renal mass underwent nephrectomy. Histopathology revealed a segmental GCK with epithelial hyperplasia of the tubules and cysts. A diagnosis of TSC associated GCK was rendered. Eight other cases with similar histopathological findings were found in the literature, two of which presented as a localized mass. Usually there is no family history but the pathologic findings are similar. Awareness of the entity and its presentation as a localized mass may aid in the differential diagnosis of renal masses in infants. The pre-operative diagnosis of GCK is difficult and relies on a high degree of clinical awareness and imaging skills. Its presence should prompt the search for its etiology, particularly the exclusion of a heritable cause. The hyperplastic tubular epithelium within the glomerular cysts found in ours and other reported cases seems so characteristic that may serve as a major clue for the diagnosis of TSC.

A case of thyroid fibromatosis, a rare lesion of this gland.

Thyroid fibromatosis is a very rare lesion; to our knowledge, there are only four cases reported in the medical literature. Herein, we report the clinical case of a woman with thyroid fibromatosis with a long follow-up (11 years). A 63-year-old female patient, with an increasing multinodular goitre without compressive symptoms, was admitted to total thyroidectomy. The histology revealed a spindle-cell proliferation with fibroblastic characteristics with no atypia and thin capillary vessels. Immunohistochemistry was positive for beta-catenin, focally to desmin and alfa-actin and negative for cytokeratins and CD34. Thyroid cells did not display any features of papillary thyroid cancer. These characteristics were compatible with thyroid fibromatosis. For the past 11 years, the patient has been periodically followed up with neck CTs and she has not shown any signs of recurrence. Thyroid fibromatosis has been associated with invasion of surrounding structures in previous reported cases. However, this aggressive behaviour was not observed in our patient. The most challenging differential diagnosis is with papillary thyroid cancer with fibromatosis-like stroma, in which the malignant component is usually peripheral. Therefore, in these cases, it is mandatory to perform an extensive examination of the resected sample. LEARNING POINTS: Fibromatosis is a mesenchymal lesion that consists of an infiltrative proliferation of fibroblasts without atypia.Thyroid fibromatosis is a rare entity in this gland. In previously reported cases, it has been associated with an invasive behaviour but this was not the case in our patient.When spindle-cell proliferation with fibroblastic/myofibroblastic characteristics is detected on thyroid histology, it is mandatory to exclude a papillary thyroid carcinoma with fibromatosis-like stroma.

Chondrosarcoma of the hyoid bone: A diagnostic pitfall in the submandibular region.

Chondrosarcoma is a malignant chondroid matrix-producing neoplasm which usually presents in the bones of the pelvis, followed by the proximal femur, proximal humerus, distal femur and ribs. The occurrence of this lesion in the hyoid bone is exceedingly rare, with only a few reported cases, and its diagnosis by fine-needle aspiration cytology (FNAC) in this particular location, to our knowledge, has never been addressed. Furthermore, the sampling of chondroid matrix at this site can pose a diagnostic dilemma with other lesions of the submandibular region. This report describes the clinical, radiologic and cytologic features on FNAC of a chondrosarcoma of the hyoid bone, emphasizing the diagnostic pitfalls of this entity and expanding the cytologic differential diagnosis of tumors of the submandibular region.

Adrenocortical oncocytoma presenting as Cushing's syndrome: an additional report of a paediatric case.

Oncocytomas are tumours predominantly or exclusively composed of oncocytes, cells with granular and eosinophilic cytoplasm filled with mitochondria. Although they can occur in every organ, they are rare in adrenal glands, and in paediatric patients they are even rarer, with only three case reports previously published. We present a preschool child developing Cushing's syndrome due to an adrenocortical oncocytoma, which was confirmed immunohistochemically with antibodies to the mitochondrial electron complex 2. A 5.8-year-old girl presented with clinical features of Cushing's syndrome. ACTH-independent hypercortisolism was confirmed biochemically and a left adrenal mass was detected by imaging and removed by laparotomy. Histopathological analysis revealed a tumour composed of more than 95 % of oncocytes, confirmed immunohistochemically with antibodies to subunits A and B of the mitochondrial enzyme succinate dehydrogenase. Using the Lin-Weiss-Bisceglia score system and the reticulin algorithm, this tumour was categorized as a benign adrenocortical oncocytoma. The patient currently has 64 months of follow-up, without any evidence of relapse of symptoms. To our knowledge, we herein present the youngest patient developing an adrenocortical oncocytoma and the first manifestation of Cushing's syndrome due to this rare neoplasm in paediatric patients. We also emphasize the clinical usefulness of immunohistochemistry to the mitochondrial enzyme succinate dehydrogenase to confirm the oxyphilic nature of adrenocortical oncocytomas.

Diagnostic pitfalls in fine-needle aspiration cytology of temporomandibular chondroblastoma: report of two cases.

Chondroblastoma is a benign bone neoplasm, which usually presents in the epiphysis of long bones, but can occur in unusual locations. This report describes the clinical, radiologic, and cytologic features on FNA of two chondroblastomas of the temporomandibular region that were only recognized by histopathologic study. This emphasizes the diagnostic pitfalls of this entity and expands the cytologic differential diagnosis of tumors of the parotid region.