Journal of Cytology
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 Table of Contents    
ORIGINAL ARTICLE  
Year : 2019  |  Volume : 36  |  Issue : 4  |  Page : 196-199
Cytological diagnosis and misdiagnosis of nodular fasciitis


1 Department of Pathology, Sarojini Naidu Medical College, Agra, Uttar Pradesh, India
2 Department of Pathology, Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India

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Date of Submission30-Jun-2018
Date of Decision04-Jun-2019
Date of Acceptance04-Jun-2019
Date of Web Publication31-Jul-2019
 

   Abstract 


Background: Nodular fasciitis (NF) is a rapidly growing, self-limiting, subcutaneous nodular cytologic exuberant fibroblastic/myofibroblastic proliferation prone to cytological misdiagnosis. Aims: This study aimed at finding out the utility of fine needle aspiration cytology (FNAC) from NF patients and to validate the diagnostic features. Materials and Methods: The study group comprised 11 cases diagnosed as NF on cytology or subsequent histology. Results: Out of 11 cases, 9 were cytologically diagnosed as NF. Two cases were misdiagnosed as sarcoma as proven histologically. Of the 9 cases of NF, spontaneous resolution occurred in 7 cases in 2–16 weeks; excisional biopsy was undertaken in the other 2 cases. Conclusion: On cytology, NF reveals hypercellular, polymorphic, dispersed cell population, which is most commonly misdiagnosed as sarcoma. For this reason, FNAC has to be correlated with clinical data and followed up for the anticipated spontaneous regression.

Keywords: Fibroblast/myofibroblast, fine needle aspiration, nodular fasciitis, pseudosarcomatous

How to cite this article:
Rani D, Gupta A. Cytological diagnosis and misdiagnosis of nodular fasciitis. J Cytol 2019;36:196-9

How to cite this URL:
Rani D, Gupta A. Cytological diagnosis and misdiagnosis of nodular fasciitis. J Cytol [serial online] 2019 [cited 2019 Oct 18];36:196-9. Available from: http://www.jcytol.org/text.asp?2019/36/4/196/263855





   Introduction Top


Nodular fasciitis (NF) is the commonest of the benign pseudosarcomatous lesions.[1] It presents as a rapidly enlarging, often painful or tender subcutaneous nodule, most often affecting young adults and showing a predilection for the upper limb, especially the forearm.[2] Owing to hypercellular, polymorphic pattern of lesional cells and giant cells, NF is the most common benign lesion misdiagnosed as sarcoma on fine needle aspiration cytology (FNAC).[3] We are presenting the FNAC findings in 11 cases of NF patients.

This study was undertaken as NF and is commonly misdiagnosed as sarcoma, so a correct cytodiagnosis will prevent the patient from unnecessary mutilating surgery, as NF undergoes spontaneous regression within few weeks. Various authors in previous studies have also stated that clinical course of NF is completely benign and typically regresses within a few months without surgery or treatment of any kind, it can be very challenging diagnostically, often mimicking a malignant process due to its rapid growth clinically and its high cellularity, mitotic activity and variable/non-specific cytomorphologic findings.[4],[5],[6]


   Materials and Methods Top


The study group comprised a total of 11 cases. Nine of these were cases of NF diagnosed cytologically and verified histologically (two cases)/clinically (through regression in seven cases). Two cases had been misdiagnosed cytologically as sarcoma. We performed the standard FNAC procedure using 22-gauge needle. Air-dried smears were prepared and examined on site to determine the adequacy of the samples. Smears were then fixed in methanol and stained with May-Grunwald Giemsa and studied cytologically. Histology and immunohistochemistry with SMA and CD68 were undertaken in four cases. Seven cases underwent spontaneous regression during follow-up period of 16 weeks.


   Results Top


There were 11 cases of NF, comprising 5 males and 6 females, with an age range of 17–40 years. The most common location in our series was upper extremity (6 cases), followed by chest wall (2 cases), 1 case each from lower extremity, neck and from preauricular region. In all the cases, there was a history of rapidly enlarging subcutaneous nodule, ranging in size from 1 to 3 cm. There was a short clinical history in all the cases, ranging from 1 to 4 weeks.

In all the patients, FNAC was performed. Cytological diagnoses and their clinical course are given in [Table 1]. In 11 cases aspirated, 9 cases were diagnosed as NF and 2 cases were misdiagnosed as sarcoma. These two cases were diagnosed as NF on histology. On clinical follow-up of the 9 cases diagnosed cytologically as NF, spontaneous regression occurred in 7 cases in 2–16 weeks. In the remaining 2 cases, excisional biopsy was undertaken on account of rapid growth, which engendered anxiety in the patient and/or clinician.
Table 1: Clinical follow-up of the 11 cases

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Cytomorphologic features of 11 cases are listed in [Table 2]. The aspirates were highly cellular in 8 cases; 2 cases had moderate cellularity, while low cellularity was seen in 1 case only. Myxoid stroma was seen in all the cases. The case with low cellularity had abundance of myxoid stroma. Almost all the cases had dispersed cells along with few tissue fragments. Cells were polymorphic, having spindle, round, oval to triangular shape. Cells had cytoplasmic processes and round to ovoid nucleus. Few binucleate/trinucleate cells were seen in all the cases. Nuclear chromatin was finely granular, having one to two nucleoli. There were few cells with abundant cytoplasm, resembling ganglion cells. In most of the cases, few inflammatory cells such as mast cells, lymphocytes, histiocytes and histiocytic giant cells were also seen. Mitotic figures were frequently noted in all the cases, but no atypical mitosis was seen [Figure 1]a, [Figure 1]b, [Figure 1]c.
Table 2: Cytological features of nodular fasciitis

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Figure 1: (a) Smears showing dispersed cells, as well as a tissue fragment in a myxoid background (May Grunwald Giemsa stain, ×100). (b) Aspirate showing polymorphic cells with abundant cytoplasm and finely granular chromatin. Mitotic figure is also noted (May Grunwald Giemsa stain, ×400 (c) Aspirate showing polymorphic cells with few lymphocytes and a histiocytic giant cell (May Grunwald Giemsa stain, × 400)

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Histopathology was done in four cases and it confirmed the diagnosis of NF [Figure 2]a. Immunohistochemistry for smooth muscle actin and CD68 was positive in all the four cases and was negative for desmin [Figure 2]b. The diagnosis can be aided by the identification of the USP6-MYH9 gene fusion.
Figure 2: (a) Biopsy showing oval to spindle shaped cells in short fascicles and extravasated erythrocytes (Hematoxylin and eosin, ×100). (b) Nodular fasciitis showing positive immunostaining for smooth muscle actin (SMA), ×200 and CD 68, ×400, while Desmin, ×200 was negative

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   Discussion Top


NF is a pseudosarcomatous, self-limiting reactive process composed of fibroblasts and myofibroblasts. It may occur in patients of any age, but is most common in adults 20–40 years of age. NF may occur anywhere on the body, the most common sites being upper extremities, followed by trunk, chest wall and back.[7] It is considered to occur due to unusual proliferation of myofibroblasts triggered by local injury or inflammatory process.[8] In our study, clinical features with regard to age, location and duration of symptoms were similar to those previously published.

NF is most commonly misdiagnosed as spindle cell sarcoma, owing to its rapid growth, high cellularity, cellular as well as nuclear polymorphism and mitotic activity. In our study, 2 cases out of 11 (18 per cent) were misdiagnosed as sarcoma. However, sarcoma can be differentiated from NF on the basis of long duration of history, larger size of tumour, occurrence in late adult life and most frequently on lower extremities. Plaza et al. reported that two-third of their cases had been misdiagnosed as sarcoma.[9] NF has to be clearly distinguished from spindle cell sarcoma on the basis of degree of cytologic atypia, which is marked in spindle cell sarcoma.[10] Wong believe that distinction of NF from sarcoma can be made on FNAC, provided the clinical course is also taken into account.[11]

On FNAC, NF has to be distinguished from other benign and malignant spindle cell neoplasms, such as benign fibrous histiocytoma (BFH), myxoma, inflammatory myofibroblastic tumour (IMFT) and myxofibrosarcoma. NF sometimes presents with multinucleated giant cells and few or no ganglion cell-like cells; it may then be confused with BFH. Short duration of lesion and rapid growth are in favour of NF. Few NF cases show low cellularity with very prominent myxoid change, then diagnosis of myxoma is rendered, but it is deeply located lesion.[1]

IMFT closely resembles NF on cytology, but is commonly intra-abdominal, has bland-looking spindle cells and prominent inflammatory background. Myxofibrosarcoma can be distinguished from NF on the basis of its long history, occurrence in patients above 50 years of age. On cytology, curvilinear blood vessels are characteristic.[1] Various authors have discussed cytologic differential diagnosis of NF and have mentioned features of assistance in distinguishing it from other spindle cell neoplasms.[11],[12],[13]

NF is a self-limiting reactive process. There are few reports where FNAC was done and spontaneous resolution occurred within 2–16 weeks.[11],[13],[14] In our study, 7 cases out of 11 (67 per cent) underwent spontaneous resolution within 2–16 weeks, while excisional biopsy was undertaken in 4 cases. Of these 4 cases, 2 were misdiagnosed as sarcoma, while in other 2 cases, excisional biopsy was undertaken to allay apprehension of the patient.

To conclude, NF is a pseudosarcomatous lesion that can be correctly diagnosed if the cytologist is aware of the clinical as well as cytologic features (high cellularity, dispersed cells, cell polymorphism and myxoid background) and the potential for misdiagnosis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Domanski HA, Akerman M, Silverman J. Soft tissue and musculoskeletal system. In: Gray W, Kocjan G, editors. Diagnostic Cytopathology. 3rd ed. London: Elsevier; 2010. p. 755–808.  Back to cited text no. 1
    
2.
Fletcher CDM. Tumors of soft tissue. In: Fletcher CDM, editor. Diagnostic Histopathology of Tumors. 4th ed. Philadelphia: Elsevier Saunders; 2013. p. 1796–870.  Back to cited text no. 2
    
3.
Powers CN, Berardo MD, Frable WJ. Fine-needle aspiration biopsy: Pitfalls in the diagnosis of spindle-cells lesions. Diagn Cytopathol 1994;10:232–40.  Back to cited text no. 3
    
4.
Plaza JA, Mayerson J, Wakely PE. Nodular fasciitis of the hand. Am J Clin Pathol 2005;123:388–93.  Back to cited text no. 4
    
5.
Kong CS, Cha I. Nodular fasciitis: Diagnosis by fine needle aspiration biopsy. Acta Cytol 2004;48:473–77.  Back to cited text no. 5
    
6.
Berry AB, Jaffee I, Greenberg M, Eisele DW, Ljung BM. Nodular fasciitis: Definitive diagnosis by fine needle aspiration. Acta Cytol 2016;60:19–24.  Back to cited text no. 6
    
7.
Goldblum JR, Folpe AL, Weiss SW. "Enzinger and Weiss's Soft Tissue Tumors". 6th ed. St Louis: Mosby; 2014. p. 190–201.  Back to cited text no. 7
    
8.
Cyriac MJ, Celine MI, Kurien G, Puthiode U. Nodular fasciitis. Indian J Dermatol Venereol Leprol 2004;70:239–41.  Back to cited text no. 8
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9.
Plaza JA, Mayerson J, Wakely PE Jr. Nodular fasciiitis of the hand: A potential diagnostic pitfall in fine-needle aspiration cytopathology. Am J Clin Pathol 2005;123:388–93.  Back to cited text no. 9
    
10.
Mahon JH, Folpe AW, Ferlic RJ. Intraneural nodular fasciitis: Case report and literature review. J Hand Surg Am 2004;29:148–53.  Back to cited text no. 10
    
11.
Wong NL. Fine needle aspiration cytology of pseudosarcomatous reactive proliferative lesion of soft tissue. Acta Cytol 2002;46:1049–55.  Back to cited text no. 11
    
12.
Singh S, Paul S, Dhall K, Khichy S. Nodular fasciitis: A diagnostic challenge. Indian J Pathol Microbiol 2013;56:288–90.  Back to cited text no. 12
    
13.
Allison DB, Wakely PE, Siddiqui MT, Ali SZ. Nodulfasciitis: A frequent diagnostic pitfall on fine needle aspiration. Cancer Cytopathol 2017;125:20–9.  Back to cited text no. 13
    
14.
Stanley MW, Skoog I, Tani EM, Horwitz CA. Nodular fasciitis: Spontaneous resolution following diagnosis by fine-needle aspiration. Diagn Cytopathol 1993;9:322–24.  Back to cited text no. 14
    

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Correspondence Address:
Dr. Deepa Rani
Department of Pathology, Sarojini Naidu Medical College, 31/188, Kaveri Vihar, Phase I Road, Agra - 282 002, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JOC.JOC_112_18

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