Phenotypic Cytoskeletal Heterogeneity in Melanoma, a Challenge to the Surgical Pathologist Evaluating a Poorly Differentiated Neoplasm: An Illustrative Case

Characterization of poorly differentiated neoplasms can be a challenging task for the surgical pathologist. It is essential that the entire spectrum of immunomorphologic findings of various tumors be recognized to avoid improper characterization of a given neoplasm, which may in turn adversely affect patient management. Tumor characterization is complicated by the immunomorphologic transformations that malignant cells may undergo by virtue of which they may depart from expression of expected features and acquire new, unexpected characteristics. Traditionally, amelanotic melanomas have been difficult to characterize because of the diversity of their light microscopic morphology (epithelioid, spindle, and combined varieties). As a result, several other neoplasms are usually considered in the differential diagnosis. This report describes a primarily spindle-cell amelanotic melanoma that created a diagnostic dilemma, which could only be resolved by combining the information obtained from extensive evaluation by means of several diagnostic techniques. This case also stresses the phenotypic heterogeneity of the cytoskeleton of malignant melanomas and therefore their varied immunomorphologic characteristics.     

Thoracoscopic Assisted Pneumonectomy

A lung carcinoma with tumor involving more than one lobe or in close proximity to the mainstem bronchus often requires pneumonectomy for surgical cure. Inflammation, bulky tumors, and dense adhesions limit the operative field of vision and may result in the abandonment of procedures with potential for complete extirpation. This case illustrates the utility of thoracoscopy in visualization of the hilum and other neurovascular structures in a patient with a proximal tumor and dense intrathoracic adhesions. Successful resection was made possible by use of combined open and thoracoscopic modalities.     

Osgood-Schlatter lesion: fracture or tendinitis? Scintigraphic, CT, and MR imaging features.

To determine whether the Osgood-Schlatter lesion (OS) is produced by avulsion fracture or injury to the patellar tendon, all images obtained in 28 cases of OS in 20 patients (16 scintigrams, 34 computed tomographic [CT] scans, and 27 magnetic resonance [MR] images) were retrospectively analyzed. In 21 cases, imaging was performed before and after treatment; in 20 cases, relief from pain was complete at the time of repeat examination. In all patients (100%), abnormal size of the tendon, decreased attenuation, and increase in signal intensity were compatible with the CT and MR imaging appearance of tendinitis. Distended deep infrapatellar bursa was a frequent finding, particularly on MR studies. These abnormalities had partially disappeared at follow-up examination. An ossicle was seen in only nine of 28 cases (32%); in three of seven cases with follow-up, the ossicle remained nonunited to the tibial tuberosity on follow-up studies despite relief from symptoms. This implies that healing of fracture is not essential for relief from symptoms. These results strengthen the argument that in most cases of OS, insult to the tendon and associated soft tissues, rather than avulsion fracture, causes OS.     

Neurocysticercosis in Persons with Epilepsy in Medellín,Colombia

Summary: Purpose: A prospective series of 643 persons with epilepsy attending a reference neurologic center in Medellin, Colombia, was examined by computed tomography (CT scan) or serology or both with the enzyme-linked immunoelectrotransfer blot assay (EITB) to assess the prevalence of Taenia solium cysticercosis. Methods: All presenting patients were consecutively enrolled in the study. Five hundred forty-six persons underwent cerebral CT scans; 376 of them also had serum EITB performed. Results: Prevalence of neurocys@ercosis by CT scan was 13.92%. Overall prevalence of T. solium antibodies with EITB was 9.82%, but for those with late-onset epilepsy (onset after age 30 years), prevalence increased to 17.5% and 19% for those who originated from outside urban Medellin. Seroprevalence in individuals with mixed lesions (cysts and calcifications) was 88.2% and 64.10% in those with live cysts. Conversely, only 2.72% of persons with CT findings not related to neurocysticercosis had positive EITB tests. Conclusions: Our study shows that an important proportion of individuals with epilepsy have radiologic or serologic evidence of T. solium infection, suggesting that neurocysticercosis is an important etiology for epilepsy in Colombia.     

Trisomy 4 as the sole cytogenetic abnormality in a Waldenström macroglobulinemia

We report a case of Waldenstr?m macroglobulinemia with trisomy 4 as the sole cytogenetic abnormality. Trisomy 4 has been reported previously in Waldenstr?m macroglobulinemia, but only in conjunction with multiple chromosomal aberrations. Trisomy 4 has been reported in other hematologic malignancies including acute myeloid and lymphoid leukemias.     

Alteration of the LRP1B gene region is associated with high grade of urothelial cancer

We have delineated regions of interest at chromosome 2q21.2, 2q36.3, and 2q37.1 by deletion mapping of 114 urothelial cancers (UC). Altogether, 17%, 18%, and 63% of the G1, G2, and G3 tumors displayed loss of heterozygosity at chromosome 2q, respectively, The region at 2q21.2 was narrowed down to the LRP1B gene (NT_005129.6). Hemi- and homozygous deletion at the LRP1B gene region was seen in 31 of 114 UCs. Only 8% of the UCs with G1 and none with G2 tumors showed loss of heterozygosity at the LRP1B gene, whereas 49% of the G3 UCs had allelic loss at this region. RT-PCR analysis of the LRP1B gene showed the lack of expression of several exons in 2 of 9 cases analyzed. Our analysis suggests that the LRP1B gene is a candidate tumor suppressor gene in UCs.     

Electron microscopy renders the diagnostic capabilities of cytopathology more precise: an approach to everyday practice

Cytology is a powerful diagnostic tool but to make definitive diagnoses, the use of ancillary techniques is imperative. By combining immunohistochemistry (IHC) and electron microscopy (EM), cytologic diagnoses can be as precise as those of surgical pathology. In the authors' daily practice of cytopathology they use all ancillary techniques available to them: histochemistry, IHC, EM, flow cytometry, and molecular pathology. IHC is frequently used as an ancillary technique in their daily practice but EM is many times their technique of choice. By the use of EM the authors can make specific final diagnoses, make the diagnosis more definitive, narrow the differential diagnosis, or determine the origin of a neoplasm with unknown primary site. Specimens obtained by fine-needle aspiration as well as all body fluids are suitable for EM. The limiting factor is to obtain the appropriate material with the diagnostic cells for ultrastructural examination. The common diagnostic dilemmas in the everyday practice of cytology are the following: mesothelioma vs. adenocarcinoma, neuroendocrine differentiation or not, the distinction of melanoma from adenocarcinoma and sarcoma, hepatocellular carcinoma vs. adenocarcinoma, and the origin of adenocarcinomas of unknown primary. The authors discuss how they approach these diagnostic problems in their everyday practice and how they incorporate EM in solving them.