D2-40, a novel immunohistochemical marker in differentiating dermatofibroma from dermatofibrosarcoma protuberans.

The distinction between dermatofibroma, particularly cellular variant, and dermatofibrosarcoma protuberans in excisional biopsies is usually straightforward. However, a separation between the two may be sometimes challenging, especially in superficial biopsies. Although factor XIIIa and CD34 immunostains are useful in differentiating dermatofibroma and dermatofibrosarcoma protuberans in most instances, focal CD34 positivity may be seen in cellular fibrous histiocytoma. Some cases reveal overlapping immunostain results. D2-40 identifies a 40-kDa O-linked sialoglycoprotein present on a variety of tissues including testicular germ cell tumors as well as lymphatic endothelium. In this study, we investigated the utility of D2-40 in separating dermatofibroma from dermatofibrosarcoma protuberans and compared the results with other commonly used immunostains. Fifty-six cases of dermatofibroma (including six cellular variant) and 29 cases of dermatofibrosarcoma protuberans were retrieved from the archives of Department of Anatomic Pathology at Sunnybrook Health Sciences Center in University of Toronto. We applied factor XIIIa, CD34, and monoclonal mouse anti-D2-40 immunostains to formalin-fixed, paraffin-embedded tissue sections. All 56 (100%) cases of dermatofibroma demonstrated strong and diffuse immunoreactivity to D2-40 in the spindle cells and stroma. Similarly, factor XIIIa showed strong and diffuse positivity in the spindle cells. Nearly all dermatofibromas were negative for CD34 except one case revealing focal positivity. None of dermatofibrosarcoma protuberans cases were labeled by D2-40, although four cases showed weak and patchy background staining in contrary to diffuse, strong, and crisp staining seen in dermatofibromas. Our results indicate that D2-40 seems to be a sensitive immunohistochemical marker for dermatofibromas, including cellular variant. Focal and faint D2-40 staining may be seen in the stroma of dermatofibrosarcoma protuberans. Our findings suggest that D2-40 can be used as a complementary immunostain to factor XIIIa and CD34 in problematic and challenging cases on superficial biopsies.

Peritoneal elastic lamina invasion: limitations in its use as a prognostic marker in stage II colorectal cancer.

Peritoneal involvement in colorectal cancer (CRC) is an adverse prognostic feature, which may prompt consideration of adjuvant chemotherapy in stage II disease. Controversies and challenges surrounding its assessment have led to consideration of peritoneal elastic lamina invasion (ELI) as an alternative marker of advanced local spread. The objectives of this study were (1) to evaluate the prognostic significance of peritoneal ELI in stage II CRC and (2) to determine the feasibility of ELI assessment in routine practice with the use of an elastic stain. Two hundred seventeen patients with stage II CRC (186, pT3; 31, pT4) were assessed for ELI and other established adverse histologic features. Of the pT3 tumors, 31 (16.7%) were ELI positive, 121 (65%) were ELI negative, and 34 (18.3%) lacked an identifiable elastic lamina. There were no significant differences in disease-free survival between pT3 ELI-negative and ELI-positive tumors (P = .517). The disease-free survival of pT4 tumors was significantly lower than that of pT3 ELI-negative tumors (P = .024) and pT3 ELI-positive tumors (P = .026), respectively. The elastic lamina was detected less frequently in right-sided pT3 tumors compared with left-sided tumors (65/91 [71.4%] versus 87/95 [91.6%], P < .001). Right-sided tumors were also associated with a reduction in the staining intensity of the elastic lamina (P < .001). In conclusion, peritoneal ELI was not an adverse prognostic factor in this study. The frequent absence of an identifiable elastic lamina, particularly in right-sided tumors, may limit the use of ELI as a prognostic marker in CRC.

Ewing's family of tumors of the sinonasal tract and maxillary bone.

The Ewing's family of tumors (EFT) are malignant neoplasms affecting children and young adults. Most cases arise in the long bones or the pelvis. Primary EFT of head and neck is uncommon and primary sinonasal EFT is even rarer. Previous studies have not focused on the sinonasal region specifically, and the published literature on sinonasal EFT consists of sporadic case reports. Fourteen cases of sinonasal EFT were available and had H&Es for review and immunohistochemical stains for CD99, S100, keratins, synaptophysin and desmin. FISH or RT-PCR was performed for EWSR1 abnormalities on 8 cases. The 14 identified patients included 5 males and 9 females, ranging from 7-70 years of age (mean 32.4 years). Tumors involved nasal cavity (5), sinuses (5) or both (4). Five patients had dural, orbital or brain involvement. The majority involved bone radiologically and/or microscopically. All cases were composed of small cells with variable cytoplasmic clearing. Focal or prominent nesting was noted in most cases. All cases were positive for CD99. Keratins (AE1/3 and/or CAM5.2), S100 and synaptophysin were positive in 4, 3 and 5 cases, respectively. All cases were negative for desmin. The 8 cases tested by FISH or RT-PCR were positive for EWSR1 abnormalities. Follow-up in 8 patients ranged from 1-168 months (average 11.3 m) showing 1 death due to metastatic disease, 1 death due to local disease, 1 patient alive with metastases and 5 patients disease-free at last follow-up. Interestingly, however, an analysis of the literature suggests a better prognosis for sinonasal EFT than EFT overall.

Development and testing of fiber-reinforced composite space maintainers.

PURPOSE: The purpose of this study was to develop a clinically acceptable, cheaper, and more expedient alternative to standard stainless steel band and loop space maintainers. METHODS: Loops of fiber-reinforced composites were constructed using polyethylene fiber (Ribbond) and glass fiber (Sticktech). The loops were bonded on extracted third molars and tested for flexural strength before and after thermocycling and following repair of the appliances after initial stress failure. Bacterial colonization on the appliances was also compared. Conventional stainless steel band and loop space maintainers cemented with Ketac were controls. RESULTS: Ribbond samples demonstrated higher flexural strength than Sticktech and the control (P<.05). No differences were noted among the other samples and the control. The repaired Ribbond samples were statistically comparable in flexural strength to the initial samples. Thermocycling resulted in decreased flexural strength of both Ribbond and Sticktech (P<.05). Thermocycled Ribbond samples were comparable to the control, but a lower flexural strength was noted for Sticktech samples (P<.05). While all space maintainers allowed some bacterial adhesion, Sticktech showed higher Streptococcus mutans counts than Ribbond (P=.06). CONCLUSIONS: Ribbond space-maintainers are comparable to the stainless steel in terms of physical strength and biofilm formation. The fiber-reinforced composite space maintainers may be a clinically acceptable and expedient alternative to the conventional band-loop appliance.