Evidence for colorectal sarcomatoid carcinoma arising from tubulovillous adenoma.

Sarcomatoid carcinomas of the colorectum are rare tumors that display both malignant epithelial and stromal components. Clinically, they are aggressive tumors with early metastasis. Due to their infrequent occurrence, the pathogenesis is poorly understood. We report a case of a 52-year-old woman who presented with a rectal mass and intermittent hematochezia. Superficial biopsies during colonoscopy revealed a tubulovillous adenoma with high-grade dysplasia. Endoscopic ultrasonography confirmed an invasive nature of the mass, and deeper biopsies revealed the presence of neoplasm with mixed histological components. The surgically-excised specimen demonstrated the presence of poorly differentiated spindle cells underneath the tubulovillous adenoma and an intermediate stage of invasive adenocarcinoma. Based on the histological appearance and immunohistochemical studies, a diagnosis of sarcomatoid carcinoma was made. Only nine cases of sarcomatoid carcinomas of the colorectum have been reported to date. As a result, the terminology and pathogenesis of sarcomatoid carcinoma remain speculative. To the best of our knowledge, this is the first report of co-existence of sarcomatoid carcinoma and invasive adenocarcinoma with tubulovillous adenoma; all stages represented within the same tumor. This observation supports the "monoclonal theory" of pathogenesis with an adenoma-sarcoma progression with or without an intermediate stage of carcinoma.

Myxoinflammatory fibroblastic sarcoma with complex supernumerary ring chromosomes composed of chromosome 3 segments.

Myxoinflammatory fibroblastic sarcoma is a rare, recently described, and distinctive low-grade tumor of soft tissue. To our knowledge, there is only one previous report on the cytogenetics of this tumor. That case showed complex structural abnormalities, including a reciprocal translocation between chromosomes 1 and 10 [t(1;10)(p22;q24)] with loss of chromosomes 3 and 13. We describe here a second case showing supernumerary ring chromosomes, and a derivative chromosome 13, with additional material on the short arm. We conclude that the presence of chromosomal abnormalities supports the neoplastic nature of this tumor and aids in its diagnosis. Furthermore, we also postulate that the finding of ring chromosomes, which have been identified in other low-grade soft-tissue tumors, may have important prognostic implications regarding the aggressiveness of this neoplasm.

Ossifying fibromyxoid tumor of the ethmoid sinus in a newborn: report of a case and literature review.

Ossifying fibromyxoid tumor (OFT) of soft parts is a benign soft tissue tumor commonly located in the extremities. In this paper, a 3-week-old boy presented with left nasal mass at birth. He was found to have an OFT involving the ethmoid sinus. To the best of our knowledge, this is the first reported case of OFT in a newborn with involvement of the sinuses. This rare tumor should alert Pediatric Otolaryngologists to include it in the differential diagnosis of pediatric soft tissue tumors in sinuses.

Indeterminate diagnosis in fine-needle aspiration of the pancreas: reasons and clinical implications.

An indeterminate diagnosis made on fine-needle aspiration (FNA) samples of the pancreatic lesions can cause dilemmas in clinical management. We retrospectively analyzed FNA features of such lesions in 65 consecutive pancreatic FNAs from 56 lesions to learn more about the sources of uncertainty and their clinical implications. A definitive diagnosis based on follow-up information was available in 50 lesions. Radiologically, 39% of the lesions showed a cystic component, and 25% of the lesions were ill-defined. Cytologically, contributing factors included scant atypical cells, coexistence of gastrointestinal epithelium, pancreatitis, poor cellular preservation, and interpretation error. Repeat sampling, as requested by clinicians prior to treatment, was performed in 33 (66%) of the 50 lesions, leading to a definitive pathologic diagnosis in 20 (61%) lesions. Seventeen lesions were eventually resected, of which a definitive preoperative diagnosis was attempted in 12 lesions via repeat sampling and was successful in seven. We concluded that indeterminate cytologic diagnosis of a pancreatic lesion often needs to be pursued for optimal management. Although intrinsic natures of a lesion such as cystic component may contribute to insufficient sampling, diagnostic certainty can be improved by proper specimen handling, interpretation, and clinical and/or radiographic correlation.

Merkel cell carcinoma in a malignant pleural effusion: case report.

BACKGROUND: Merkel cell (neuroendocrine) carcinoma is a small round blue cell malignant neoplasm that primarily presents in the skin. The diagnosis of Merkel cell carcinoma in a pleural fluid is challenging because of the morphological similarity to many other malignant neoplasms. Immunohistochemical stains can be essential to establish the diagnosis of Merkel cell carcinoma. CASE PRESENTATION: A 77 year-old woman presented with a mass in her right buttock thought clinically to be a boil or sebaceous cyst. Upon histopathologic review including immunohistochemical analysis, a diagnosis of Merkel cell carcinoma was rendered. Wide-excision and sentinel lymph node biopsy revealed negative margins and no evidence of metastasis. Ten months later she complained of bone pain and a bone scan revealed multiple lesions. An abdominal CT scan revealed a T4 vertebral mass and local radiotherapy was administered. Two months later the patient presented with shortness of breath. A chest radiograph showed an effusion and thoracentesis was performed. The fluid was confirmed to contain metastatic Merkel cell carcinoma by cytology and immunohistochemical analysis. CONCLUSIONS: Merkel cell carcinoma is an aggressive neoplasm that can, despite careful surgical management, occasionally present as a malignant pleural effusion in a relatively short time period. Immunohistochemical analysis can aid in confirming this rare outcome.