Brief reports 265
Radiation-induced malignant schwannoma is often a fatal tumour. Predisposing factors, such as von Reck- linghausens disease5, must be recognized so that radia- tion treatment of malignant disease is optimal to give maximum efficacy with minimal morbidity.
Acknowledgements We wish to acknowledge Professor D.Crowther and Dr C.K.Heffernan for permission to publish case 1 ; Professor J.McClure for his advice: Dr S.Banik for photographic and other assistance; and Miss M.D.Garner for secre- tarial assistance.
References 1 . Cavanagh JB. Etrects of X-irradiation on the proliferation of cells in
peripheral nerve during Wallerian degeneration in the rat. Br. 1. Rndiol. 1968: 41: 275-278.
2. Shore-Freedman I
was minimally tender. By the next day the abdomen was more tender and his haemoglobin had dropped from 12 g/I. on admission. to 7 . 5 g/l. Laparotomy showed a n enlarged ruptured spleen and splenectomy was per- formed: he made a n uneventful recovery. Histological examination of the operative specimen having suggested ii diagnosis of infectious mononucleosis. a Paul Bunnell test wiis subsequently found to be positive and atypical lymphocytes were identified in the peripheral blood. The patient later admitted a severe pharyngitis several weeks ear I ier .
A 30-year-old male lorry driver presented with acute left sided loin pain. There was no previous history and in particular he denied trauma. On examination he was found to have a n acute abdomen and laparotomy
Figure 2. 'I'rabeculiir inliltration by atypical lymphoid cells \$:it11 adiaccnt epithelioid granulomas.
14 I S T 0 1' A T H 0 1.OG I ('A I . F I N I) I N G S I
In each case the spleen showed expansion of the red pulp with prolileration of atypical lymphocytes. together with multiple epithelioid granulomas (Figure 1 ). There was no associated necrosis and the granulomas occurred predominantly at the marginal zones of the white pulp. 'I'here was extensive trabecular and capsular infiltration by atypical lymphoid cells (Figure 2 t . which stained positively for the T-cell marker UCHL- 1. In addition. there ~ri i s local sub-endothelial and medial infiltration of
Figure 1 . Epithelioid granulomas at the marginal zone of splenic white pulp.
Figure 3. a Suh-entlothelial inliltralion by atypical lymphoid ~('11s. b Mcdial inliltriition by atypical lymphoid cells.
Brief reports 267
Discussion Splenic granulomas are rare. Neiman4 examined 4 12 splenectomy specimens and found epithelioid granulo- mas in only 24. Thirteen of these were from patients with Hodgkins disease, three had non-Hodgkins lym- phoma, three had chronic uraemia. four had sarcoidosis and one patient suffered from a chronic immunodeti- ciency disorder associated with selective IgA deficiency. Two of the 412 specimens were from patients with infectious mononucleosis and neither of these showed epithelioid granulomas. In 19 74 Kuo & Kosai reviewed 20 cases of splenic granulomas and reported that, in the majority of cases. a specific diagnosis could not be made. None of this group of 2 0 cases had infectious mono- nucleosis.
The granulomas in our cases were situated predomi- nantly within the peripheral zones of the white pulp, were small and showed a sprinkling of lymphocytes and no associated necrosis. This description is in accord with the type 1 lesion described by Kuo CL Kosai and is the most commonly occurring type of splenic granuloma.
A thymic origin for the atypical lymphoid cells in infectious mononucleosis was proposed by Sheldon et al. in 1973 and in our cases these cells stained with the T-cell marker UCHL-1. It has been suggested that T-cells are important in the initiation. maintenance and resolu-
tion of granulomas7 and that cytokines, in particular interleukin-1, play a major role.
The subintimal infiltration of splenic vessels by atypi- cal lymphoid cells is recognized4. However, this, together with the medial infiltration seen in our cases, is worthy of emphasis, since it is a feature more usually associated with malignant lymphoid proliferations and may give rise to confusion.
References Burke IS. Surgical pathology of the spleen: an approach to the diagnosis of splenic lymphomas & leukaemias. A m . I . Surg. fantliol. 19x1 : 5: 68 1-694. Harrison CV. Lymph nodes in infectious mononucleosis. In Har- rison CV ed. H w m t Advntws in Pntltokcig,~/. London: J & A Churchill. 19hh: 2 10. Kothwell DJ. Bone marrow granulomas and infectious mononuc- leosis. Ardi. fcftllol. 1975: 99; 5(18-509. Neinian KS. Incidence & importance of splenic sarcoid-like granulo- mas. Arb. fcitlrol. I , c ~ J . M d . 1977: 101 : 5 18-52 1. Kuo T. Rosai I . Granulomatous inflammation in splenectomy specimens. Arch. P d o l . I9 74: 98: 26 1-268. Sheldon PJ, Iapamichail M . Hemsted EH. Holborow El. Thymic origin of atypical lymphocytes in infectious mononucleosis. Loticut 1973:i : 1153-1155. Sheffield EA. The granulomatous inflammatory response. /. Iatlrol. 19YO: 160: 1-2.
Symmetrical fibro-osseous dysplasia of rib - evidence for a traumatic aetiology
D.K.GOULDESBROUGH Department of Pnthology, University o/ Edinburgh, Scotland. UK
Date of submission 1 3 November 1989 Accepted for publication 28 February 1990
Keywords: dysplasia, rib, trauma
Clinically similar lesions in the ribs with atypical histological features are known . Reed suggested these differ from fibrous dysplasia and a traumatic aetiology for these lesions has been s~ggested.~. The term sym- metrical fibro-osseous dysplasia was coined4. In this report two cases of fibro-osseous dysplasia are described. Firm evidence for a post traumatic aetiology is presented, one case developing at a previous fracture site.
Introduction Fibrous dysplasia in the rib is an expansile lesion. Its histology is well established and varies with the site2. Address for correspondence: Dr D.R.Couldesbrough, Department of Pathology, University of Edinburgh. Teviot Place, Edinburgh EH8 9AG. UK.