Irradiated Skeletal Muscle Cells Mimicking Those of Atypical Fibroxanthoma on Mohs Frozen Sections.

ABSTRACT: Radiation can induce changes to skeletal muscle cells that may mimic and thus be confused with cells of atypical fibroxanthoma (AFX), pleomorphic dermal sarcoma, spindle cell squamous cell carcinoma, and other spindle soft-tissue tumors. An 80-year-old White man presented for Mohs micrographic surgery of an AFX on the left lateral neck. The medical history was notable for a tongue squamous cell carcinoma 9 years before that had been treated with wide local excision, left neck dissection, and radiation to the oral cavity and left neck. Frozen sections from the first stage of Mohs did not show typical AFX, but did reveal patchy clusters of atypical spindled and epithelioid cells, some with multiple nuclei. Because of the unusual appearance of these cells, Mohs micrographic surgery was halted, and the frozen tissue block was sent for permanent pathology examination. The cells on permanent sections stained positive for desmin, revealing them to be of skeletal muscle origin (in this case damaged platysma muscle because of late postradiation changes). It is thus important for the Mohs surgeon and the consultant dermatopathologist to be aware of the unusual histologic appearance of irradiated skeletal muscle to avoid confusion with other spindle cell tumors.

Correlation of Suture Diameter With Its Ability to Cut Through an Artificial Skin Model.

BACKGROUND: Sutures can tear through tissue, but little data exist on the relative ability of different suture gauges and suture types to cut into the skin. OBJECTIVE: To quantify the relative ability of various sutures to cut into and tear through the skin. METHODS AND MATERIALS: We tested 4 suture types (polypropylene, nylon, polyglactin 910, and poliglecaprone 25) at 2 gauges each (3-0 and 5-0) in their ability to cut into and tear through an artificial skin substitute comprised of a 1-mm thick silicone sheet. The force required to cut into and through the skin substitute was measured using a digital force gauge that generated a force-time curve. The suture diameters were verified using both a precision caliper micrometer and an eyepiece micrometer with the microscope. Statistical analysis was performed using the Student t-test and analysis of variance. RESULTS: All 5-0 suture types required less force to cut into and tear through the skin substitute than their 3-0 counterparts. Among each suture gauge, there was no significant difference in tear-through force regardless of the suture type. CONCLUSION: Compared with larger gauge sutures, smaller gauge sutures more easily cut into and tear through skin substitute.

Assessment of Materials to Prevent Sutures Cutting Through Atrophic Skin.

BACKGROUND: Sutures can tear through thin skin, especially in the elderly. To reinforce thin skin, several materials have been suggested through which sutures may be placed. OBJECTIVE: To evaluate the relative tear-through resistance to suture provided by various materials applied to a skin substitute. MATERIALS/METHODS: We measured the force needed for 3-0 polypropylene suture to tear through an artificial skin substitute, both alone and after various materials were applied. These materials included wound closure tapes, nonwoven polyester tape, hydrocolloid dressing, polyethylene film, and cyanoacrylate glue. The Student t-test and one-way analysis of variance were used to determine differences in the mean forces. RESULTS: Reinforced wound closure tape and nonwoven polyester tape were superior to the other materials, and provided a 3.1-fold and 3.6-fold increase in tear-through resistance, respectively, compared with skin substitute alone (p < .001). Orientation of wound closure tape and nonwoven polyester tape with their reinforcing fibers placed parallel to the skin substitute edge provided increased tear-through resistance compared with perpendicular placement. Affixing these latter materials with liquid adhesive also improved holding strength. CONCLUSION: Reinforced wound closure tape and nonwoven polyester tape, when applied to a skin substitute, provide significantly increased tear-through resistance to suture compared with skin substitute alone.

Predictors of squamous cell carcinoma in high-risk patients in the VATTC trial.

Invasive squamous cell carcinoma (SCC) of the skin is one of the most common cancers in the United States, with no proven means for prevention other than systemic retinoids, which have significant toxicity, and sunscreen. We sought to determine the risk factors for invasive SCC on the face or ears in a high-risk population comprising 1,131 veterans in the Veterans Affairs Topical Tretinoin Chemoprevention (VATTC) Trial. Participants were required to have been diagnosed with at least two keratinocyte carcinomas (KCs) in the 5 years prior to enrollment. The median duration of follow-up was 3.7 years. Twenty-three percent of the participants developed a new invasive SCC, and the cumulative risk of invasive SCC was 30% at 5 years. The following factors independently predicted for new invasive SCCs: number of invasive SCCs and number of in situ SCCs in the 5 years prior to enrollment, actinic keratoses count at enrollment, a history of ever use of topical 5-fluorouracil, and total occupational time spent outdoors. In contrast, the use of angiotensin-convering enzyme inhibitors or angiotensin receptor blockers during the study and a history of warts anywhere on the body were found to protect against new invasive SCCs. These independent predictors remained the same for all SCCs (invasive and in situ combined). The number of basal cell carcinomas in the 5 years prior to enrollment, sunburns, sun sensitivity, and recreational sun exposure were not associated with new SCCs. These findings identify key risk factors for additional SCCs in patients with multiple prior KCs, and suggest that a history of warts may be associated with reduced SCC risk.