Intraosseous myoepithelioma: a rare, distinct tumor entity.

Primary musculoskeletal myoepithelial tumors (METs) are distinctly rare tumors and are being increasingly recognized as a result of improved diagnostic criteria and objective confirmation with immunohistochemical markers, including epithelial markers. Recent studies have unraveled distinct molecular mechanisms underlying these tumors. Herein, we present our second diagnosed case of an intraosseous MET that occurred in the tibia of a 37-year-old lady. The case is discussed with regards to current clinicopathological perspectives on these rather uncommon tumors, including our personal experience.

Pathology of Ewing's sarcoma/PNET: Current opinion and emerging concepts.

Ewing's sarcoma/PNET are small round cell tumors showing a varying degree of neuroectodermal differentiation. They are one of the commonest tumors of childhood and occur in bone and within soft tissues. Traditionally, light microscopy with the aid of immunohistochemical stains was suitable for diagnosis. But now translocation analyses are being used not only for the diagnosis and classification of small round cell tumors, but to ascertain their prognostic significance, detect micrometastasis, and monitor minimal residual disease, with potential for targeted therapy. This article analyzes the pathology, biology, and molecular aspects of Ewing's sarcoma/PNET and discusses their clinical and therapeutic implications.

How does knowledge of three-dimensional excision margins following breast conservation surgery impact upon clinical target volume definition for partial-breast radiotherapy?

BACKGROUND AND PURPOSE: To compare partial-breast clinical target volumes generated using a standard 15 mm margin (CTV(standard)) with those generated using three-dimensional surgical excision margins (CTV(tailored 30)) in women who have undergone wide local excision (WLE) for breast cancer. MATERIAL AND METHODS: Thirty-five women underwent WLE with placement of clips in the anterior, deep and coronal excision cavity walls. Distances from tumour to each of six margins were measured microscopically. Tumour bed was defined on kV-CT images using clips. CTV(standard) was generated by adding a uniform three-dimensional 15 mm margin, and CTV(tailored 30) was generated by adding 30 mm minus the excision margin in three-dimensions. Concordance between CTV(standard) and CTV(tailored 30) was quantified using conformity (CoI), geographical-miss (GMI) and normal-tissue (NTI) indices. An external-beam partial-breast irradiation (PBI) plan was generated to cover 95% of CTV(standard) with the 95% isodose. Percentage-volume coverage of CTV(tailored 30) by the 95% isodose was measured. RESULTS: Median (range) coronal, superficial and deep excision margins were 15.0 (0.5-76.0)mm, 4.0 (0.0-60.0)mm and 4.0 (0.5-35.0)mm, respectively. Median CoI, GMI and NTI were 0.62, 0.16 and 0.20, respectively. Median coverage of CTV(tailored 30) by the PBI-plan was 97.7% (range 84.9-100.0%). CTV(tailored 30) was inadequately covered by the 95% isodose in 4/29 cases. In three cases, the excision margin in the direction of inadequate coverage was

Adamantinoma of tibia: a study of 12 cases.

BACKGROUND: Adamantinoma is a rare tumor of long bones that can be mistaken for a carcinoma, and numerous other lesions such as myoepithelial tumor, malignant mixed tumor of bone, fibrous dysplasia/osteofibrous dysplasia, and vascular tumors. METHODS: The histology and clinical features of 12 cases accrued from the surgical pathology files over a period of 23 years were analyzed. RESULTS: Of the 12 cases, 4 were men and 8 women, with a mean age of 30 years. Radiologically the tumor presented as a lytic, eccentric, intracortical lesion in the tibia. The histology revealed epithelial islands with basaloid, spindle, and squamous features on a background of fibrotic stroma. Three patients came back with local recurrences, and one of them developed pulmonary metastasis. DISCUSSION: In this article, an attempt is made to study the morphology, biology, and the differential diagnoses of adamantinoma of long bones.

Melanin bearing myoepithelial cells in a pigmented salivary gland carcinoma: a new avatar of myoepithelial cell? A case report.

Melanocytes can be found in the stroma of salivary glands and their tumors. However, the presence of melanin pigment in the tumor cells of salivary gland origin is exceedingly rare. A 42-year-old man presented with a nasal tumor that was black in color. The histology was that of a minor salivary gland carcinoma with foci resembling an adenoid cystic carcinoma. The myoepithelial cells of this tumor contained melanin pigment. The possible histogenesis of this lesion and an explanation for the occurrence of melanin pigment in a salivary gland tumor are discussed.

A study of histopathological features of medullary carcinoma of the thyroid: cases from a single institute in India.

BACKGROUND: The microscopic features of medullary carcinoma have been described in world literature, together with its behavior and molecular biology. However, no large study has been reported from India. AIMS: This study aims to analyse the clinical, and especially the pathological features of medullary carcinoma of the thyroid, and the surrounding thyroid. MATERIALS AND METHODS: In this study a total of 234 cases of medullary thyroid carcinoma (MTC) were gathered over a period of 3 decades. The clinical presentation, the microscopic features and the clinical outcome were analyzed. RESULTS: MTC was found to be twice as common in men as in women and for some reason it occurred 10 years earlier in women. The histology revealed certain interesting features like the presence of apoptosis in over half of the tumors, in addition to the other common and not so common histological findings (encapsulated variant, small cell variants, follicular pattern, rosettes, oncocytic change, osteosarcoma-like pattern, and cribriform pattern). The adjacent thyroid in about 19% of the cases showed optically clear nuclei in the follicles that were close to the tumor cells. These features were similar to those seen in papillary thyroid carcinoma. CONCLUSIONS: The thyroid adjacent to MTC showed nuclear changes, which are also found in papillary carcinoma of the thyroid. The occasional concurrent occurrence of these two tumors and the involvement of the RET gene in both medullary and papillary carcinomas, makes this observation worth discussing and studying further.

Chondromyxoid fibromas: a study of 10 cases.

Chondromyxoid fibroma (CMF) can be confused with a malignant tumor because of its potential for recurrence and occasional nuclear atypia. This study of 10 cases of CMF comprises 6 men and 4 women, with a mean age of 24.3 years. Tibia was the preferred site of involvement. The histology showed lobulated chondromyxoid matrix with peripheral fibrosis. Two cases had local recurrences following intralesional excision. The study emphasizes that despite nuclear atypia and recurrences, CMF is a benign disease.

Florid reactive periostitis of the hands.

Reactive periostitis of the hand can be a confounding lesion on both radiological and histological grounds. An erroneous diagnosis of a malignant tumor, particularly an osteosarcoma, is a possibility. Two cases of florid reactive periostitis of the hand mistaken for osteosarcoma are reported here to illustrate this entity and caution against a diagnostic pitfall.

Mesenchymal chondrosarcoma: a series of 23 cases.

A total of 23 cases of mesenchymal chondrosarcoma were studied from the histopathology records spanning 23 years. There were 16 men and 7 women afflicted with this tumor and their mean age was 28.1 years. The radiological features, histology and treatment outcomes have been studied. Osseous and extra-osseous mesenchymal chondrosarcomas are compared and the differential diagnosis discussed.

Langerhans' cell histiocytosis: a clinicopathological study of 50 cases.

To analyze the clinicopathologic features and outcome of patients with Langerhans cell histiocytosis (LCH). Fifty cases of LCH accrued over a 15-year period were analyzed and classified as having unifocal, multifocal, or multisystem disease. Events regarding progression, relapse, or death were noted. The 50 cases comprised of 34 men and 16 women. 92% of the patients were less than 15 years of age and 46% were less than 2 years. Involvement by LCH was unifocal in 22, multifocal in 8, and multisystem in 20. Bone was the commonest site (92%), followed by lymph node (30%). The histological features were relatively uniform regardless of the clinical severity, and consisted of Langerhans cells, eosinophils, histiocytes, plasma cells, giant cells and fibrosis. The treatment consisted of surgery, chemotherapy, and/or radiotherapy. Response to treatment was poor in patients with multisystem disease. The histology of LCH is very characteristic and patients with age less than 2 years are more likely to have increased risk or morbidity and mortality, due to widespread disease.