Path. Res. Pract. 188,350-356 (1992)
T eaching Cases
Plexiform Fibrohistiocytic Tumor Report of a Case involving Preoperative Aspiration Cytology and Immunohistochemical and Ultrastructural Analysis of Surgical Specimens L. Angervall, L. G. Kindbiom, K. Lindholm and S. Eriksson Department of Pathology, Gothenburg University, Sahlgren Hospital, Gothenburg; Department of Cytology, Malmö Allmänna Sjukhus, Malmö; and Department of Pathology, Norra Älvsborgs läns lasarett, Trollhättan, Sweden
SUMMARY A typical case of plexiform fibrohistiocytic tumor (Enzinger and Zhang2 ) occurring in the skin qnd subcutis of the abdominal wall in a 7-year-old girl is reported. Preoperative fine-needle aspiration cytology revealed a benign lesion with fibroblastic-histiocytic features wh ich also contained bi- and multinucleated giant cells. The surgical specimen showed a tumor with multiple small nodules within fibrous septa; these nodules were composed of spindie cells and epithelioid cells and contained scattered multinucleated osteoclast-like cells. The tumor cells showed ultrastructural and immunohistochemical features of myofibroblasts and histiocyte-like cells. Thus, there was an abundance of lysosomes, prominent filopodia and bundles of thin cytofilaments along the cytoplasmic border, as weil as immunoreactivity for a-smooth-muscle-specific actin, a-l-antitrypsin and a-l-antichymotrypsin. Ultrastructurally there were tumor cells exhibiting features of histiocytes which also contained bundles of actin of smooth muscle type. The presented case of plexiform fibrohistiocytic tumor appears to be composed of a rather peculiar cell form, somewhere between myofibroblasts and histiocytes.
Introduction
Recently, Enzinger and Zhang2 reported 65 cases of a previously undescribed cutaneous/subcutaneous, slowgrowing neoplasm with morphologic features reminiscent of both fibrous histiocytoma and fibromatosis. The lesion, called plexiform fibrohistiocytic tumor, occurs chiefly in children and young adults and is most commonly located in the regions of the shoulder and forearm. In about one-third of the cases the tumor recurred and, in two cases, it metastasized to regional lymph nodes. Light microscopically, the lesions were characterized by a plexiform or multinodular proliferation of fibroblast- and histiocytelike cells associated with multinuclear giant cells. The 0344·0338/92/0188·0350$3.50/0
immunohistochemical analysis revealed a positivity for a-l-antitrypsin and a-l-antichymotrypsin in three of eleven and three of ten cases, studied respectively. Electron microscopy performed in five cases on paraffin-embedded material revealed multinucleated cells and cells with the features of fibroblasts or myofibroblasts, but characteristic histiocyte-like cells with lysosomes and multiple filopodia were not observed. "In this report a typical case of plexiform fibrohistiocytic tumor with preoperative fine-ne edle aspiration cytology (FNAC) and immunohistochemical and ultrastructural analysis indicating that the majority of the tumor cells have features of myofibroblasts and histiocytes, is presented. © 1992 by Gustav Fischer Verlag, Stuttgart
Plexiform Fibrohistiocytic Tumor · 351 Case Repürt Für a few weeks a 7-year-old girl had noticed a slow-growing lesion in the abdominal wall to the right oE the navel. The surgeon who was consulted (May 1989), palpated a subcutaneons mass which could be moved in relationship to the superEicial muscle fascia. FNAC revealed a fibroblastic histiocytic cell popula tion reported as possibly being of reaetive nature and without signs oE malignancy. A complete excision was made of a diffusely delimited lesion with a diameter of about 1.5 centimeters which involved the dermis and the subcutis. After 8 ~onths there are no signs of loeal recurrence or m etastaSIS.
instructions except for a prolonged incubation time for the primary anti sera (16 h at4°C). The end products were visualized by treating the sections with a freshly-made solution of 0.05 % DAB with 0.02 % HzO z in TBS pH 7.4. The primary antisera and their concentrations are given in Table 1.
Electron Micl'Oscopy The formaldehyde-fixed pieces of tissue were washed in 0.1 M sodiumcacodylate buffer, postfixed with 1 % osmiumtetroxide for 1 hour, th ereafter d ehydrated in eth anol and embeddcd in epoxy resin. One-micron thick sections were stained with toluidine blue and ultratbin sections cut on an LKB Ultratome III wcre contrast stained with uranyl acetate and lead citrate and examined under a CM 12 Philips electron microscope. Results
Material and Methods
Light Microscopy
Light Microscopy Fine-needle aspiration was performed by the dinician and the air-dried smears were stained according to May-GrünwaldGiemsa. Five-micron sections were cut from the paraffin blocks of the formaldehyde-fixed tissue and stained according to van Gieson's trichrome staining and witb hematoxylin-eosin. Gordon's and Sweet's silver impregnation was used to visualize reticulin. Tbe Berliner blue reaction was performed to demonstrate bemosiderin. For tbe demonstration of Ulex Europeus agglutinin(UEA I)-binding a biotin labeled UEA I Sigma ( Chemical Co., St Louis, MO, U~A) was used and visualized with a peroxidase labeled avidin-biotin complex with di aminobenzidine (DAß) as the chromogen. For immunohistochemical analysis the avidin-biotin (ABC) method was applied to formaldehyde-fixed and paraffin-embedded tissues. For some of the antibodies the sections werc treated with 0.05 % trypsin T ( ype III-S, Sigma Chemical Co. ) in Tris buffer-saline (TBS) pH 7.8 for 20 min at 3rC (see Table 1). All the sections were then treated with 0.5 % HzO z in meth anol in order to reduce endogenous peroxidase activity. The ABCmethod was performed using the Vectastain® ABC-kits (Vectastain, Vector labs, Burlingame, CA, USA) according to the
Cytology: FNAC revealed a moderate number of mostly dissociated fibroblast- and histiocyte-like eells wirh regu-
•
Table 1. The antibodies, their concentrations and the results of the immunohistochemical analysis Antibody
Vimentin a a-srnooth-rnuscle-speeific aetin b Cytokeratin, KL-l c Cyrokeratin, CAM 5.2 d Cyrokeratin, AE I /AEY S-100 protein f al-anti trypsin' al-antiehymotrypsin' Faeror VIII related antigen' Maerophage, CD 68'
Results Dilution T rypsinization
M M M M M P P P P M
Fibroblasr- Multinuand histio- cleated cyte-like giant eells eells
1:20 + 1:800 + 1:500 (T) 1:4 (T) 1:300 (T) 1:3000 1:800 (T) + 1:400 (T) + 1:500 (T) 1:200
(+ )
(+ ) (+ )
+
M = monoclonal, P = polyclonal, T = trypsinization, + = most eells positive, (+ ) = few eells positive, - = no cells positive. -'Dakopatts, Glostrup, Denmark. - bSigma Chemieal Co, Sr Louis, MO, USA. - 'Immunoteeh, Marseille, France.dBeeron-Dickinson, Mountain View, CA, USA. - cBoehringer-Mannheim, Germany, - fD epa rtment of Hisrology, University of Göteborg, Swcden.
Fig. '1. Finc-Ileedle aspiration cytology smear showing mononudear fibroblast- and histiocyte-like celJs some of which have a rather abundant cytoplasm with small vacuoles and numerous granules. A larger tumor cell with three nudei an d a gran ulated cytoplasm i s seen at th e bottom right. May-Grünwald-Giemsa stain, x 400.
,
" • •• )
-r
./ I
. f
.
..
~
,.
.
.
(
.., ....
~
/
I
t
L I
/
,. I
,
)
I
.J,
..
\
, 1 ,-
. ~
0
Plexiform Fibrohistiocytic Tumor· 353
lar, round to oval nuclei. The nuclei contained regular, round nucleoli. The irregular cytoplasm often contained vacuoles and granules as signs of phagocytosis. 5cattered bi- and multinucleated osteoclast-like cells were also found (Fig.1). Histopathology: At the low-power microscopic examination the lesion had a plexiform or nodular structure. The lesion was growing diffusely within the lower two-thirds of the corium and the subcutis. In the subcutis, the tumor nodules chiefly occurred in the broad interlobular fibrous septa (Fig. 2 A). At higher magnification the tumor nodules had a fairly uniform appearance and were composed of dense collections of fibroblast- and epithelioid histiocytelike cells and interspersed multinucleated giant cells of osteoclast type (Fig. 2 B). The majority of the tumor cells were epithelioid and histiocyte-like. Both the histiocytelike and the fibroblast-like cells, the latter tending to appear at the periphery of the nodules, had a nucleus with a thin membrane and a loose chromatin texture and often contained one or two distinct nucleoli. The centrally located epithelioid cells appeared to be dissociated and mingled with the deeply stained, often basophilic, fairly small osteoclast-like giant cells (Fig. 2 B). There was no bin ding to the tumor cells of Ulex Europeus 1. A few tumor nodules were also infiltrated by lymphocytes (Fig. 2 C). The tumor cells had a slightly eosinophilic, often foamy cytoplasm. Within the tumor nodules there were scattered mast-ceHs, which were easily identified by their metachromasia in the toluidine-blue-stained 1 f.t sections. Here and there hemorrhages were seen and some hemosiderin appeared in tumor cells. The periphery of the tumor nodules, in particular, revealed a distinct network of reticulin which enclosed individual tumor cells. One tumor nodule protruded into the lumen of a medium-sized subcutaneous vein (Fig. 2 D). Immunohistochemistry
The results of the histochemical stainings are given in Table 1. Most of the spindle-shaped and epithelioid tumor cells stained positively for a-1-antitrypsin, a-1-antichymotrypsin, vimentin and a-smooth-muscle-specific actin (Fig. 3). There was no positivity for 5-100 protein or cytokeratins. In contrast to the majority of the tumor cells, the multinucleated, osteoclast-like giant cells were negative for a-smooth-muscle specific actin and they were positive for an anti-macrophage antibody (CD 68). Electron Microscopy
Ultrastructurally, the rounded and spindle-shaped tumor cells had basically the same appearance with several features of both histiocytes and myofibroblasts. The cells
T eaching Cases
Plexiform Fibrohistiocytic Tumor Report of a Case involving Preoperative Aspiration Cytology and Immunohistochemical and Ultrastructural Analysis of Surgical Specimens L. Angervall, L. G. Kindbiom, K. Lindholm and S. Eriksson Department of Pathology, Gothenburg University, Sahlgren Hospital, Gothenburg; Department of Cytology, Malmö Allmänna Sjukhus, Malmö; and Department of Pathology, Norra Älvsborgs läns lasarett, Trollhättan, Sweden
SUMMARY A typical case of plexiform fibrohistiocytic tumor (Enzinger and Zhang2 ) occurring in the skin qnd subcutis of the abdominal wall in a 7-year-old girl is reported. Preoperative fine-needle aspiration cytology revealed a benign lesion with fibroblastic-histiocytic features wh ich also contained bi- and multinucleated giant cells. The surgical specimen showed a tumor with multiple small nodules within fibrous septa; these nodules were composed of spindie cells and epithelioid cells and contained scattered multinucleated osteoclast-like cells. The tumor cells showed ultrastructural and immunohistochemical features of myofibroblasts and histiocyte-like cells. Thus, there was an abundance of lysosomes, prominent filopodia and bundles of thin cytofilaments along the cytoplasmic border, as weil as immunoreactivity for a-smooth-muscle-specific actin, a-l-antitrypsin and a-l-antichymotrypsin. Ultrastructurally there were tumor cells exhibiting features of histiocytes which also contained bundles of actin of smooth muscle type. The presented case of plexiform fibrohistiocytic tumor appears to be composed of a rather peculiar cell form, somewhere between myofibroblasts and histiocytes.
Introduction
Recently, Enzinger and Zhang2 reported 65 cases of a previously undescribed cutaneous/subcutaneous, slowgrowing neoplasm with morphologic features reminiscent of both fibrous histiocytoma and fibromatosis. The lesion, called plexiform fibrohistiocytic tumor, occurs chiefly in children and young adults and is most commonly located in the regions of the shoulder and forearm. In about one-third of the cases the tumor recurred and, in two cases, it metastasized to regional lymph nodes. Light microscopically, the lesions were characterized by a plexiform or multinodular proliferation of fibroblast- and histiocytelike cells associated with multinuclear giant cells. The 0344·0338/92/0188·0350$3.50/0
immunohistochemical analysis revealed a positivity for a-l-antitrypsin and a-l-antichymotrypsin in three of eleven and three of ten cases, studied respectively. Electron microscopy performed in five cases on paraffin-embedded material revealed multinucleated cells and cells with the features of fibroblasts or myofibroblasts, but characteristic histiocyte-like cells with lysosomes and multiple filopodia were not observed. "In this report a typical case of plexiform fibrohistiocytic tumor with preoperative fine-ne edle aspiration cytology (FNAC) and immunohistochemical and ultrastructural analysis indicating that the majority of the tumor cells have features of myofibroblasts and histiocytes, is presented. © 1992 by Gustav Fischer Verlag, Stuttgart
Plexiform Fibrohistiocytic Tumor · 351 Case Repürt Für a few weeks a 7-year-old girl had noticed a slow-growing lesion in the abdominal wall to the right oE the navel. The surgeon who was consulted (May 1989), palpated a subcutaneons mass which could be moved in relationship to the superEicial muscle fascia. FNAC revealed a fibroblastic histiocytic cell popula tion reported as possibly being of reaetive nature and without signs oE malignancy. A complete excision was made of a diffusely delimited lesion with a diameter of about 1.5 centimeters which involved the dermis and the subcutis. After 8 ~onths there are no signs of loeal recurrence or m etastaSIS.
instructions except for a prolonged incubation time for the primary anti sera (16 h at4°C). The end products were visualized by treating the sections with a freshly-made solution of 0.05 % DAB with 0.02 % HzO z in TBS pH 7.4. The primary antisera and their concentrations are given in Table 1.
Electron Micl'Oscopy The formaldehyde-fixed pieces of tissue were washed in 0.1 M sodiumcacodylate buffer, postfixed with 1 % osmiumtetroxide for 1 hour, th ereafter d ehydrated in eth anol and embeddcd in epoxy resin. One-micron thick sections were stained with toluidine blue and ultratbin sections cut on an LKB Ultratome III wcre contrast stained with uranyl acetate and lead citrate and examined under a CM 12 Philips electron microscope. Results
Material and Methods
Light Microscopy
Light Microscopy Fine-needle aspiration was performed by the dinician and the air-dried smears were stained according to May-GrünwaldGiemsa. Five-micron sections were cut from the paraffin blocks of the formaldehyde-fixed tissue and stained according to van Gieson's trichrome staining and witb hematoxylin-eosin. Gordon's and Sweet's silver impregnation was used to visualize reticulin. Tbe Berliner blue reaction was performed to demonstrate bemosiderin. For tbe demonstration of Ulex Europeus agglutinin(UEA I)-binding a biotin labeled UEA I Sigma ( Chemical Co., St Louis, MO, U~A) was used and visualized with a peroxidase labeled avidin-biotin complex with di aminobenzidine (DAß) as the chromogen. For immunohistochemical analysis the avidin-biotin (ABC) method was applied to formaldehyde-fixed and paraffin-embedded tissues. For some of the antibodies the sections werc treated with 0.05 % trypsin T ( ype III-S, Sigma Chemical Co. ) in Tris buffer-saline (TBS) pH 7.8 for 20 min at 3rC (see Table 1). All the sections were then treated with 0.5 % HzO z in meth anol in order to reduce endogenous peroxidase activity. The ABCmethod was performed using the Vectastain® ABC-kits (Vectastain, Vector labs, Burlingame, CA, USA) according to the
Cytology: FNAC revealed a moderate number of mostly dissociated fibroblast- and histiocyte-like eells wirh regu-
•
Table 1. The antibodies, their concentrations and the results of the immunohistochemical analysis Antibody
Vimentin a a-srnooth-rnuscle-speeific aetin b Cytokeratin, KL-l c Cyrokeratin, CAM 5.2 d Cyrokeratin, AE I /AEY S-100 protein f al-anti trypsin' al-antiehymotrypsin' Faeror VIII related antigen' Maerophage, CD 68'
Results Dilution T rypsinization
M M M M M P P P P M
Fibroblasr- Multinuand histio- cleated cyte-like giant eells eells
1:20 + 1:800 + 1:500 (T) 1:4 (T) 1:300 (T) 1:3000 1:800 (T) + 1:400 (T) + 1:500 (T) 1:200
(+ )
(+ ) (+ )
+
M = monoclonal, P = polyclonal, T = trypsinization, + = most eells positive, (+ ) = few eells positive, - = no cells positive. -'Dakopatts, Glostrup, Denmark. - bSigma Chemieal Co, Sr Louis, MO, USA. - 'Immunoteeh, Marseille, France.dBeeron-Dickinson, Mountain View, CA, USA. - cBoehringer-Mannheim, Germany, - fD epa rtment of Hisrology, University of Göteborg, Swcden.
Fig. '1. Finc-Ileedle aspiration cytology smear showing mononudear fibroblast- and histiocyte-like celJs some of which have a rather abundant cytoplasm with small vacuoles and numerous granules. A larger tumor cell with three nudei an d a gran ulated cytoplasm i s seen at th e bottom right. May-Grünwald-Giemsa stain, x 400.
,
" • •• )
-r
./ I
. f
.
..
~
,.
.
.
(
.., ....
~
/
I
t
L I
/
,. I
,
)
I
.J,
..
\
, 1 ,-
. ~
0
Plexiform Fibrohistiocytic Tumor· 353
lar, round to oval nuclei. The nuclei contained regular, round nucleoli. The irregular cytoplasm often contained vacuoles and granules as signs of phagocytosis. 5cattered bi- and multinucleated osteoclast-like cells were also found (Fig.1). Histopathology: At the low-power microscopic examination the lesion had a plexiform or nodular structure. The lesion was growing diffusely within the lower two-thirds of the corium and the subcutis. In the subcutis, the tumor nodules chiefly occurred in the broad interlobular fibrous septa (Fig. 2 A). At higher magnification the tumor nodules had a fairly uniform appearance and were composed of dense collections of fibroblast- and epithelioid histiocytelike cells and interspersed multinucleated giant cells of osteoclast type (Fig. 2 B). The majority of the tumor cells were epithelioid and histiocyte-like. Both the histiocytelike and the fibroblast-like cells, the latter tending to appear at the periphery of the nodules, had a nucleus with a thin membrane and a loose chromatin texture and often contained one or two distinct nucleoli. The centrally located epithelioid cells appeared to be dissociated and mingled with the deeply stained, often basophilic, fairly small osteoclast-like giant cells (Fig. 2 B). There was no bin ding to the tumor cells of Ulex Europeus 1. A few tumor nodules were also infiltrated by lymphocytes (Fig. 2 C). The tumor cells had a slightly eosinophilic, often foamy cytoplasm. Within the tumor nodules there were scattered mast-ceHs, which were easily identified by their metachromasia in the toluidine-blue-stained 1 f.t sections. Here and there hemorrhages were seen and some hemosiderin appeared in tumor cells. The periphery of the tumor nodules, in particular, revealed a distinct network of reticulin which enclosed individual tumor cells. One tumor nodule protruded into the lumen of a medium-sized subcutaneous vein (Fig. 2 D). Immunohistochemistry
The results of the histochemical stainings are given in Table 1. Most of the spindle-shaped and epithelioid tumor cells stained positively for a-1-antitrypsin, a-1-antichymotrypsin, vimentin and a-smooth-muscle-specific actin (Fig. 3). There was no positivity for 5-100 protein or cytokeratins. In contrast to the majority of the tumor cells, the multinucleated, osteoclast-like giant cells were negative for a-smooth-muscle specific actin and they were positive for an anti-macrophage antibody (CD 68). Electron Microscopy
Ultrastructurally, the rounded and spindle-shaped tumor cells had basically the same appearance with several features of both histiocytes and myofibroblasts. The cells
