Epithelioid lymphangioleiomyomatosis‐like tumour of the uterus in a patient without tuberous sclerosis: a lesion mimicking epithelioid leiomyosarcoma

Abstract

Sir : In the November 1997 issue of Histopathology, Bussolati et al. describe the restoration of endogenous biotin reactivity following antigen retrieval (using pressure cooking and to a lesser extent microwave retrieval). 1 The authors suggest that blocking of endogenous biotin by sequential avidin-biotin treatment prevents the erroneous detection of biotin.Intra-nuclear biotin inclusions have been previously misinterpreted to be those of Herpes simplex virus (HSV), using the streptavidin-biotin complex (Strep-ABC). 2 We have also described biotin intranuclear inclusions in gestational endometria closely resembling HSV inclusions. 3,4 This error can be easily avoided by paying careful attention to the negative control. We have noted the negative control to be invariably positive, due to the presence of endogenous biotin, with the StrepABC immunodetection system. This false positive immunoreaction should be the clue to the alert pathologist that there is endogenous biotin reactivity. Despite attempts to block endogenous biotin with free avidin and biotin as recommended, 1,5 we have demonstrated residual positivity in the negative control, using the StrepABC system. 4 We have also compared the alkaline-phosphataseanti-alkaline phosphatase (APAAP) and the peroxidaseanti-peroxidase (PAP) detection systems and found that whilst the negative control was negative with the former, there was aberrant immunoreactivity with the PAP system. Curiously this was eliminated with microwave pretreatment prior to immunohistochemistry. 4 These curious results serve to underscore the complexities of antigen retrieval. We use retrieval methods such as pressure cooking, microwave technology and even ultrasound, barely understanding the mechanisms of antigen retrieval. It is inevitable that aberrant and puzzling results are obtained. 6 It is imperative that diagnostic pathologists interpret immunohistochemical findings in the light of positive and negative controls, and also with full knowledge of the pitfalls and limitations of the varying detection systems used in their laboratories.We advocate that the optimal detection system for immunohistochemistry in the tissues containing endogenous biotin, as so comprehensively demonstrated by Bussolati et al. 1 is either the APAAP or PAP immunodetection system (the latter with microwave pretreatment), rather than the StrepABC method. Embarrassing and potentially dangerous errors can thus be avoided.

Abdominopelvic Sarcoma of Perivascular Epithelioid Cells. Report of Four Cases in Young Women, One with Tuberous Sclerosis

“…Recent reports have considerably widened the spectrum of PEC lesions reporting them in the uterus, pancreas and in the falciform ligament (7)(8)(9)(10)(11). PEC tumors can mimic renal clear cell carcinoma (12)(13)(14)(15)(16)(17) epithelioid leiomyosarcoma (18), hepatocellular carcinoma (19,20) conventional leiomyosarcoma or other high grade sarcomas.…”

Perivascular epithelioid cell (PEC) tumors of the uterus: a clinicopathologic study of two cases with aggressive features

“…Both patterns of growth have been described in tumors arising in the uterus. 15,17,19 The perivascular epithelioid cell tumors of the uterus have usually shown benign behavior. 13,16,19 but eleven tumors, two of them associated with TSC, were aggressive (Table 1).…”

“…2 These neoplasms have a broad spectrum of morphology and behavior and may involve the kidney, lung, liver, pancreas, common bile duct, jejunum, rectum, falciform ligament of the liver, heart, urinary bladder, prostate, breast, bone, soft tissues [3][4][5][6][7][8][9][10] and female genital tract organs, 11,8 among which the uterus is the most frequently involved. 3,4,[12][13][14][15][16][17][18][19] In this site, most of these tumors are benign or of uncertain malignant potential, 4,13,16,19 although rare malignant cases have been reported. 3,12,14,15,17,18 We report the clinicopathologic features of two perivascular epithelioid cell tumors ('PEComa') of the uterus with aggressive features, including one malignant and one with uncertain malignant potential.…”

“…3,4,[12][13][14][15][16][17][18][19] In this site, most of these tumors are benign or of uncertain malignant potential, 4,13,16,19 although rare malignant cases have been reported. 3,12,14,15,17,18 We report the clinicopathologic features of two perivascular epithelioid cell tumors ('PEComa') of the uterus with aggressive features, including one malignant and one with uncertain malignant potential.…”

Predicting the Behavior of Perivascular Epithelioid Cell Tumors of the Uterine Corpus

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Perivascular epithelioid cell tumors of the uterine corpus can occur in women of any age, including prepubertal pediatric patients. 20 While 5% of all uterine PEComas occur in the context of tuberous sclerosis, most tumors seem to be sporadic.…”