A clinical and histologic review of 22 patients (13 males, 9 females) with cutaneous lesions classified as desmoplastic trichilemmoma is reported. Typically, the lesions occur as solitary dome-shaped papules on the face during (at least) the fifth decade of life. The average age was 64 years (range 19-89) with a median age of 66.5 years. The most frequent clinical diagnosis was basal cell carcinoma, and the most common sites were the lip, eyebrow and nose. Two lesions occurred in examples of nevus sebaceus of Jaddasohn. The proportion of desmoplasia varies, but is generally between 20% to 60% of the lesion. Ulceration is seen in a minority of lesions but when present, is closely associated with underlying desmoplasia. Desmoplasia may be seen in small, as well as large, trichilemmomas; it generally occurs centrally but at times may be seen peripherally. The appearance of strands of epithelial cells entrapped in dense fibrosis and hyalinization may mimic desmoplastic variants of squamous cell carcinoma and basal cell carcinoma. This appearance may be particularly troublesome when the desmoplasia occurs at the base of the biopsy specimen. Knowledge of this phenomenon and the search for more typical features of trichilemmoma such as clear cells and peripherally palisaded columnar cells upon a thickened, eosinophilic basement membrane will allow the correct diagnosis to be made. We believe that the desmoplasia occurs as a secondary change in pre-existing trichilemmomas.

Findings from T2-weighted magnetic resonance (MR) images obtained of postmortem, in vitro human brain glioma specimens were correlated with histologic findings from whole-brain sections. Eighteen cases were categorized as untreated (n = 6), in remission after surgery and radiation therapy (n = 2), or recurrent (n = 10). Findings from MR images generally correlated well with the histologic extent of untreated tumors in white matter; the heterogeneous appearance of glioblastomas multiforme distinguished them from less malignant gliomas. Subpial spread and tumor in the subarachnoid space were not visualized. The extent of tumors in remission was overestimated on MR images because of the extensive surrounding edema and radiation necrosis. MR imaging findings correlated well with those from 48% of brain slices, but resulted in overestimations (24%) or underestimations (28%) of tumor extent in the ten cases of recurrent tumor. The results suggest that information concerning the patient's stage of disease is important in interpreting MR images of gliomas.

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Ten examples of a distinctive vascular tumor are reported. These benign acquired lesions typically occur as small, enlarging lesions that favor the extremities, particularly the forearms, of young to middle-aged adults. Clinically, they are purple to red lesions generally thought to be hemangiomas. Histologically, there is a pattern of irregular, branching venules with inconspicuous lumina and lack of cellular atypia. Because the lesions do not conform to existing classifications of vascular tumors, they have been designated with the histologically descriptive name of microvenular hemangioma. Although speculative, they are felt to represent a form of acquired venous hemangioma.