Anatomical and MR correlative study of the proximal sciatic nerve vasculature.

OBJECTIVE: The aim of our study is to demonstrate that increased T2 signal on MRI could be due to intraneural vessels in asymptomatic individuals, and may therefore be a normal finding. METHODS: An initial anatomic cadaveric study was undertaken to gain a better understanding of the vascular supply of the proximal sciatic nerve. Secondly, a retrospective study of MR imaging of patients without sciatic symptoms was performed to assess the prevalence of intraneural vessels, defined as hyperintensity on at least three consecutive slices on both T2 and gadolinium enhanced T1 weighted imaging, visible on routine MSK pelvic imaging. RESULTS: The anatomical study demonstrated a relatively abundant blood supply in the peri-ischiatic region. In the MR study, 20/76 (26%) patients showed visible intraneural vessels. More than one intraneural vessel was depicted in two of the sciatic nerves. Direct branching between the extrinsic and intrinsic systems was seen in only five cases. CONCLUSION: Normal intraneural vessels can frequently be seen within the sciatic nerve on routine musculoskeletal pelvic imaging. Advances in knowledge: T2 hyperintensity in the proximal sciatic nerve can be due to intraneural vessels and should not necessarily be reported as abnormal.

Fully Regressive Melanoma: A Case Without Metastasis.

Fully regressive melanoma is a phenomenon in which the primary cutaneous melanoma becomes completely replaced by fibrotic components as a result of host immune response. Although 10 to 35 percent of cases of cutaneous melanomas may partially regress, fully regressive melanoma is very rare; only 47 cases have been reported in the literature to date. AH of the cases of fully regressive melanoma reported in the literature were diagnosed in conjunction with metastasis on a patient. The authors describe a case of fully regressive melanoma without any metastases at the time of its diagnosis. Characteristic findings on dermoscopy, as well as the absence of melanoma on final biopsy, confirmed the diagnosis.

Anatomical study of spinal accessory nerve using ultrasonography.

OBJECTIVE: The purpose of our study was to demonstrate that ultrasonography may allow a precise assessment of the course and relationships of the spinal accessory nerve (SAN). MATERIAL AND METHODS: This study, initially undertaken in 7 cadavers, was followed by high-resolution ultrasonographic study in 15 volunteers (30 nerves) by two radiologists in consensus. The location, course and relations to the adjacent anatomic structures of the SAN were analyzed. RESULTS: The precise course of the SAN between the lateroposterior border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle could be identified by high-resolution ultrasonography. In contrast, clinical bone landmarks were not found helpful for the identification of the nerve. CONCLUSION: The SAN can be clearly depicted by means of ultrasonography. Knowledge of the nerve's precise location, which may evidence individual variations, may have useful clinical applications.

Anatomical study of phrenic nerve using ultrasound.

PURPOSE: To demonstrate whether ultrasonography may allow a precise assessment of the course and relations of the phrenic nerve in its cervical portion. METHODS: This study, initially undertaken in five cadavers, was followed by high-resolution ultrasonographic study in 20 volunteers (40 nerves) by two radiologists in consensus. The location, course and relations of the phrenic nerve to the adjacent anatomical structures were analysed. RESULTS: The phrenic nerve could be nicely identified through the majority of its course by high-resolution ultrasonography. Useful anatomic landmarks for the detection of the nerve could be defined; these include the transverse cervical and ascending cervical arteries. Some anatomical variations were observed. CONCLUSION: Knowledge of the nerve's precise location, which may demonstrate individual variations, may have useful clinical applications.

Pseudoepitheliomatous epidermal hyperplasia in tattoos: report of three cases.

Cutaneous reactions to tattoos are not uncommon and various histologic patterns have been reported, including lichenoid, granulomatous, eczematous, and pseudolymphomatous reactions. Such patterns may develop with highly variable delay after the tattooing procedure. We report three strikingly similar cases of a fast-occurring, tattoo-induced, cutaneous reaction strictly restricted to the red parts of the tattoos in two cases and displaying an unusual histologic pattern, i.e. pseudoepitheliomatous hyperplasia. Clinical differential diagnosis of this rare condition includes viral warts, keratoacanthoma, and verrucous carcinoma. It may be difficult to rule out the last two diagnoses and making the diagnosis usually requires full excision of the lesion, comprehensive histologic analysis, and careful follow-up.

Metacarpophalangeal joints at US in asymptomatic volunteers and cadaveric specimens.

PURPOSE: To determine normal anatomy of metacarpophalangeal (MCP) joints at ultrasonography (US) and to compare findings with anatomic and histopathologic findings. MATERIALS AND METHODS: Right hands of five cadavers (two women, three men; age range at death, 46-96 years; mean age at death, 62 years) and dominant hands of 30 volunteers (15 men, 15 women; age range, 27-74 years; mean age, 43 years) were evaluated. Nonthumb MCP joints were scanned longitudinally and transversely by two musculoskeletal radiologists working independently at US with a high-frequency linear-array transducer (frequency, 12 MHz). US appearances of intraarticular and periarticular structures were analyzed independently by these radiologists. Specimen sectioning provided anatomic and histopathologic comparisons. Interobserver precision was assessed with determination of coefficient of variation (CV). RESULTS: Sagittal US images enabled good visualization of the dorsal metacarpal synovial recess and the metacarpal head cartilage. In 37% of cases, a small depression (mean depth, 0.3 mm) was identified on the dorsal aspect of the metacarpal head, especially at the second MCP joint (19% of cases). Direct visualization of sagittal bands of the extensor hood was possible on dorsal transverse US scans, especially at the second and third MCP joints. In all cases, the first annular pulley was well seen on palmar transverse US scans. The radial collateral ligament of the second MCP joint was better recognized by the two observers than was the ulnar collateral ligament of the fifth MCP joint. Interobserver precision was high (CV range, 1.5%-6.5%) for intraarticular and periarticular structures. CONCLUSION: US provides detailed information about normal anatomy of nonthumb MCP joints.