| clear cell | A cell in which the cytoplasm appears empty with the light microscope, as occurs in certain secretory cells of eccrine sweat glands and in the parathyroid glands when the glycogen is unstained, any cell, particularly a neoplastic one, containing abundant glycogen or other material that is not stained by haematoxylin or eosin, so that the cell cytoplasm is very pale in routinely stained sections. (05 Mar 2000) |
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| clear cell acanthoma | A sharply demarcated benign epidermal lesion of a leg or arm with acanthosis and accumulation of glycogen in keratinocytes having pale staining cytoplasm. (05 Mar 2000) |
| clear cell adenocarcinoma | <tumour> A histologic type of renal adenocarcinoma. A histologic type of adenocarcinoma occurring chiefly in the male and female genitourinary tracts which is characterised by distinctive hobnail cell growth of neoplastic cells in sheets, papillae, and coalescing glands. (05 Mar 2000) |
| clear cell carcinoma of kidney | <radiology> Hypernephroma, renal cell carcinoma, arises from proximal collecting tubule, 10% bilateral adenocarcinoma types: papillary, alveolar, onchocytoma vascularity, 85% hypervascular (require pre-op embolization), 10% hypovascular (usually papillary type), 5% avascular associated with: tuberous sclerosis, von Hippel-Lindau syndrome see also: staging (12 Dec 1998) |
| clear cell hidradenoma | <tumour> A tumour derived from eccrine sweat glands, composed of glycogen-rich clear cells. Synonym: eccrine acrospiroma, nodular hidradenoma. (05 Mar 2000) |
| clear layer of epidermis | A layer of lightly staining corneocytes in the deepest level of the stratum corneum; found primarily in the thick epidermis of the palmar and plantar skin. Synonym: clear layer of epidermis. (05 Mar 2000) |
| clear liquid diet | A diet, often used postoperatively, consisting usually of water, tea, coffee, gelatin preparations, and clear soups or broth. (05 Mar 2000) |
| water-clear cell of parathyroid | A variety of chief cell, so-called because the cytoplasm contains much glycogen that is not preserved or stained in the usual preparation. Synonym: wasserhelle cell. (05 Mar 2000) |
| sarcoma, clear cell | A sarcoma of young, often female, adults of the lower extremities and acral regions, intimately bound to tendons as circumscribed but unencapsulated melanin-bearing tumours of neuroectodermal origin. An ultrastructural finding simulates flattened and curved barrel staves, corresponding to the internal structures of premelanosomes. There is a 45-60% mortality in clear cell sarcoma. (12 Dec 1998) |
| burns, first degree | A first degree burn is superficial and has similar characteristics to a typical sun burn. The skin is red in colour and sensation is intact. In fact, it is usually somewhat painful. (12 Dec 1998) |
| ventriculography, first-pass | Radionuclide ventriculography where a bolus of radionuclide is injected and data are recorded from one pass through the heart ventricle. Left and right ventricular function can be analyzed independently during this technique. First-pass ventriculography is preferred over gated blood pool imaging for assessing right ventricular function. (12 Dec 1998) |
| Mendel's first law | Factors that affect development retain their individuality from generation to generation, do not become contaminated when mixed in a hybrid, and become sorted out from one another when the next generation of gametes is formed. Synonym: Mendel's first law. (05 Mar 2000) |
| mirror, first or front surface | <microscopy> An optical mirror on which the reflecting surface is applied to the front surface of the mirror instead of to the back, that is, to the first surface of incidence. (05 Aug 1998) |
| pregnancy trimester, first | Period of pregnancy from the first day of the last normal menstrual period through the completion of 14 weeks (98 days) of gestation. (12 Dec 1998) |
| healing by first intention | Healing by fibrous adhesion, without suppuration or granulation tissue formation. Synonym: primary adhesion, primary union. (05 Mar 2000) |