Tthyd, a new thymocyte alloantigen linked to Igh-1. Implications for a switch mechanism for T cell antigen receptors.

Tthyd is an alloantigen coded for by a gene(s) near the immunoglobulin locus on chromosome 12 in the mouse. This T cell-specific antigen may be the third member of a family of antigen receptors on T cells encoded by a cluster of genes in the IgT-C region. This antigen is preferentially expressed on thymocytes in contrast to Tindd or Tsud that are expressed on peripheral T cells. The hypothesis that T cell receptors undergo a switch in surface isotype upon maturation is discussed.

Meningioma metastatic to thyroid gland.

OBJECTIVE: To describe the first reported case of meningioma metastasizing to and completely infiltrating the thyroid gland. METHODS: We present a detailed case report, including radiographic, histologic, and immunostaining findings, in a patient with an atypical meningioma who had a progressively enlarging thyroid mass that proved to be a metastatic meningioma. RESULTS: A 49-year-old man had a meningioma in the parieto-occipital region that had spread locally to the scalp and bone by the time of surgical resection. Local recurrence during the following year prompted repeated surgical resection, tumor embolization, radiotherapy, and chemotherapy. Despite aggressive therapy, the tumor progressed. A thyroid mass was first noted 2 years after the meningioma was diagnosed. Enlargement of the mass caused airway obstruction, necessitating an emergency thyroidectomy. Histologic examination of the thyroidectomy specimen showed that the thyroid gland had been extensively replaced by metastatic meningioma. CONCLUSION: To our knowledge, this is the first reported case of metastatic meningioma extensively infiltrating the thyroid gland. This case report expands the spectrum of tumors that metastasize to the thyroid gland.

Subcutaneous Kaposi's sarcoma. Thallium scan demonstration.

A case of AIDS-related Kaposi's sarcoma involving subcutaneous tissues beyond the visible skin lesions is reported. In this case, the tumor was thallium avid. Thallium scintigraphy was able to demonstrate the true extent of the tumor and may be used to document the presence and extent of cutaneous and extracutaneous AIDS-related Kaposi's sarcoma.

Submucosal uterine leiomyomas: diagnosis of prolapse into the cervix and vagina based on MR imaging.

OBJECTIVE: We describe the MR appearance, signs and symptoms, and pathologic findings in five patients with submucosal leiomyomas that prolapsed into the cervical or vaginal canal. SUBJECTS AND METHODS: During the past 3 years, five women aged 33-53 years (mean, 43 years) were identified prospectively at MR imaging as having prolapsing uterine leiomyomas. The diagnosis was confirmed by surgical pathology. MR imaging was performed on a 1.5-T unit, using both T1- and T2-weighted spin-echo or fast spin-echo sequences. The images were analyzed for signal intensity, presence of a stalk, and caudal extent of the prolapsed leiomyoma. RESULTS: These leiomyomas, the presence of prolapse, and the caudal extent of prolapse were detected prospectively on MR images in all five cases. Prospective localization of the stalk in two cases aided subsequent hysteroscopic resection. MR imaging correctly indicated the presence of hemorrhage in one, degeneration in a second, and the absence of these complications in two others. In the fifth case, a hemorrhagic focus in the distal tip of the leiomyoma was not detected on MR images obtained 3 days before surgery. CONCLUSION: MR imaging is useful for the diagnosis and characterization of uterine leiomyomas that have prolapsed into the cervical or vaginal canal.

Female pelvis: impact of MR imaging on treatment decisions and net cost analysis.

PURPOSE: To determine the impact of gynecologic magnetic resonance (MR) imaging on treatment decisions and net cost. MATERIALS AND METHODS: Sixty-nine consecutive women were referred for 70 pelvic MR imaging examinations. Diagnosis and treatment plans were obtained from referring physicians before and immediately after they were given verbal reports of MR imaging results. Outcome regarding treatment and symptoms was obtained at a mean follow-up of 10.9 months. RESULTS: Of 49 (71%) patients originally recommended for surgery, 36 (73%) either did not undergo surgery or less invasive surgery was performed. In 58 (84%) patients, the treatment performed was that recommended after performance of MR imaging. Symptoms resolved in 57 (83%) patients. Use of MR imaging resulted in an overall savings of $63 per patient ($1,736 per patient originally recommended for surgery). CONCLUSION: Use of pelvic MR imaging in diagnosis of some gynecologic diseases may alter treatment, decrease the number of invasive surgical procedures performed, and reduce total health care expenditures.

Traumatic ileocolic pseudoaneurysm: diagnosis and transcatheter treatment.

Injuries to branches of the superior mesenteric artery are unusual and often difficult to diagnose, yet require prompt recognition and treatment to prevent exsanguinating hemorrhage or bowel ischemia. This report describes a unique case of an ileocolic artery pseudoaneurysm diagnosed using delayed CT imaging and definitively treated by transcatheter embolization. Cathet. Cardiovasc. Intervent. 48:217-219, 1999.

Magnetic resonance imaging of pathologic conditions of the Achilles tendon.

The advent of magnetic resonance imaging (MRI) has improved imaging of the Achilles tendon. Various pathologic conditions of the Achilles tendon and their MRI characteristics are described. The superior resolution of the tendon provided by MRI can aid in the diagnosis of Achilles tendon disorders, which include complete or partial rupture of the tendon as well as postoperative assessment of tendinous healing, tendinitis and tenosynovitis, and various tumors of the Achilles tendon.

Malignant priapism associated with metastatic urethral carcinoma.

We present a 40-year-old man with malignant priapism secondary to urethral squamous cell carcinoma. Magnetic resonance imaging revealed the tumor originating from the bulbous urethra, extending into the penile urethra and corpora spongiosa and cavernosa. A penile biopsy confirmed poorly differentiated squamous cell carcinoma of the urethra. Despite administration of systemic chemotherapy, the prognosis of the patient has worsened due to the extensive metastatic disease.