Journal of Clinical and Diagnostic Research. 2022 Mar, Vol-16(3): ED04-ED06 4 4 DOI: 10.7860/JCDR/2022/53505.16085 Case Report Pathology Section A Rare Mesenchymal Neoplasm in an Uncommon Anatomical Site- Solitary Fibrous Tumour of Vulva NUPUR KAUSHIK 1 , LALIT KUMAR 2 , PRASHANT SINGH 3 , JUHI SINGHAL 4 Keywords: Extrathoracic, Haemangiopericytoma, Signal transducer and activator of transcription 6 ABSTRACT Previously, Solitary Fibrous Tumour (SFT) was thought to originate from the pleura, a relatively rare mesenchymal neoplasm with an indolent course. Vulva is the very uncommon site of extrathoracic SFT. This is the report of a very uncommon case of vulval SFT in a 30-year-old female with complaint of a swelling over vulval region. Fine Needle Aspiration Cytology (FNAC) of the growth was attempted twice and only blood was aspirated. The swelling was excised completely. On histological examination, the sections revealed a cellular tumour of ovoid-to-fusiform spindle cells with indistinct cell borders, with haphazard arrangement or patternless pattern along with proliferation of variable sized blood vessels. The diagnosis was finalised to be a benign stromal tumour (most probably SFT), which was confirmed on immunohistochemical examination using Cluster of Differentiation 34 (CD34), CD99 and Signal Transducer and Activator of Transcription 6 (STAT6) markers. CASE REPORT A 30-year-old married female presented to the Obstetrics and Gynaecology outpatient department, with the history of swelling over vulval region for 14 months. The swelling was gradual in onset and progressively increasing in size. There was no significant family history, no history of intake of oral contraceptive pills or any medication with normal menstrual cycle. On local physical examination, the swelling was skin-fixed, non tender, mobile and soft to firm in consistency with cauliflower like growth on surface. FNAC of the swelling, along with pap smear was advised to the patient. FNAC was attempted twice and only blood was aspirated. Pap smear revealed superficial and intermediate squamous cells in sheets with no parabasal and basal cells. Few intermediate cells showed koilocytic changes in an acute inflammatory background. No endocervical cells were seen. No epithelial cells abnormality was seen. As per the Bethesda system of reporting of cervical cytology, pap smear was negative for intraepithelial lesion and malignancy, with presence of acute inflammation [Table/Fig-1] [1]. Ultrasonography (USG) of lower abdomen revealed uterus and bilateral tube and ovary to be within normal limit. The cervix appeared bulky measuring 3 to 7 cm in size with minimal free fluid in cul-de-sac. USG findings were suggestive of cervicitis with minimal free fluid in cul-de-sac. The swelling was excised and sent for histopathological examination. On gross examination, the specimen was a greyish- white skin covered irregular piece of tissue with multiple finger like projection measuring 3.0×3.0×1.5 cm. The cut surface showed a well circumscribed greyish white nodule beneath the skin [Table/ Fig-2]. Multiple tissue sections were processed to obtain 3 to 4 μm thick section, and stained with Hematoxylin and Eosin (H&E). On histopathological examination, the sections revealed papilliferous hyperplastic squamous epithelium; tumour nodule lying in subepithelium showing proliferation of fibroblastic cells; ovoid to fusiform spindle cells with indistinct cell borders, with haphazard arrangement or patternless pattern along with proliferation of variable sized blood vessels [Table/Fig-3-5]. Overall, histological [Table/Fig-1]: Showing superficial and intermediate squamous cells in sheets with no parabasal and basal cells seen in an acute inflammatory background (Pap smear, 40X); [Table/Fig-2]: Cut surface showing well circumscribed nodule with grey-white surface and overlying skin surface yellowish white papillary projection. (Images from left to right) [Table/Fig-3]: Showing epidermis, haemorrhagic area and well-circumscribed tumour present in sub epidermal region showing proliferation of spindle cells in hap- hazard pattern with variable sized slit like spaces. (H&E, 4X); [Table/Fig-4]: Show- ing proliferation of fibroblastic cells; ovoid to fusiform spindle cells with indistinct cell borders, with haphazard arrangement or patternless pattern along with proliferation of variable sized blood vessels (H&E, 10X). (Images from left to right) [Table/Fig-5]: Showing ovoid to fusiform spindle cells with indistinct cell borders along with proliferation of variable sized blood vessels (H&E, 40X); [Table/Fig-6]: Showing CD34 positivity of blood vessels and tumour cells (IHC, 40X). (Images from left to right)