Bone marrow metastatic
infiltration of a rabdoid pancreatic tumor
Maria Sironi, Donata Grando,* Maurizio Spinelli
Department of Pathology, and *Blood Bank Service, S. Corona
Hospital, Azienda G. Salvini, Garbagnate Milanese (MI), Italy
Correspondence:Maria Sironi. Tel 0299513233. Fax 0299513477
E-mail: merysironi@libero.it
Bone marrow aspirate shows in rare cases very unusual
features, whose interpretation is very difficult, because
haematologists have little familiarity with non haematologic (i.e.
epithelial) cells.
A 74-year-old female was referred in our Hospital in cachettic
state, with epigastric pain. In the past, she suffered because of
gastro-duodenal ulcers, with gastrointestinal haemorrage, and
colonic diverticulosis. In order to study a peripheral
leucocytosis (78000), with eosinophilia (39%), she underwent a
bone marrow aspiration, which cytology was characterized by a rich
hematopoietic population, with myelocytes and eosinophils (36%),
and by a neoplastic proliferation of large cells, with basophilic
cytoplasm and round nucleus, with granular chromatin and evident
nucleolus (Figure
1). In the meantime,
abdominal echotomographic examination showed multiple metastatic
liver lesions. Twelve days after admission, the patient died. The
autopsy revealed a necrotic pancreatic tumor, with multiple
metastases (liver, lung, adrenals, thyroid, kidney, lymphnodes,
neoplastic thrombosis of the spenic and portal veins). Histology
showed a solid and alveolar proliferation of epithelioid cells,
with large, hyperchromatic nuclei, clumped chromatin, eosinophilic
macronucleoli and dense granular eccentric cytoplasm
(Figure
2a). Immunophenotype of
tumoral cells was vimentin, cytokeratin (Cam 5.2
clone,
Figure. 2b) and actin
(HHF35 clone) positive, often in a globular dot-like appearance. A
diagnosis of malignant rabdoid tumor was made.
Malignant rabdoid tumor (MRT) was first recognized in 1978 as
rabdomyosarcomatous variant of Wilms' tumor.1
Subsequently, rabdomyoblastic origin was not proved and a
final link to Wilms' tumor was not substantiated.2
Several MRT cases arise in extrarenal sites, as prostate, heart,
soft tissue, brain, liver, lung, uterus, stomach and colon, and
would represent the dedifferentiated components of the
accompanying adenocarcinoma,3 in which the "composite"
tumor shows an admixture of "parent" tumour and "rabdoid"
components.4 Moreover, we know only one case of MRT
reported in the pancreas,5 combined with mucinous
cystadenocarcinoma. The exceptionality of our case is the bone
marrow invasion from this rare malignant tumor, of which
cytological features allowed to exclude haematologic
malignancy.
