Annals of Tropical Medicine and Public Health

CASE REPORT
Year
: 2013  |  Volume : 6  |  Issue : 3  |  Page : 347--349

Unusual presentation of calvarial tuberculosis masquerading as a cutaneous neoplasm: diagnosis by fine needle aspiration cytology


Prem Singh1, Ankita Goyal1, Aparna Tanwar1, Sanjeev Sharma2,  
1 Department of Pathology, M. M. Institute of Medical Sciences and Research, Mullana, Ambala, Haryana, India
2 Department of Radiodiagnosis, M. M. Institute of Medical Sciences and Research, Mullana, Ambala, Haryana, India

Correspondence Address:
Prem Singh
Department of Pathology, M. M. Institute of Medical Sciences and Research, Mullana, Ambala, Haryana
India

Abstract

Calvarial tuberculosis is a rare entity forming 0.2-1.3% of skeletal tuberculosis. Primary calvarial tuberculosis without evidence of tuberculous lesion elsewhere in the body is still rarer and sometimes clinically mimics cutaneous neoplasm. We describe a case of young girl who presented with swelling on the scalp in the region of the left frontal bone. She was suspected to be case of cutaneous neoplasm. Diagnosis was confirmed by Fine Needle Aspiration Cytology supplemented by radiological and microbiological investigations. The patient responded well to Anti-tubercular therapy without any surgical intervention.



How to cite this article:
Singh P, Goyal A, Tanwar A, Sharma S. Unusual presentation of calvarial tuberculosis masquerading as a cutaneous neoplasm: diagnosis by fine needle aspiration cytology.Ann Trop Med Public Health 2013;6:347-349


How to cite this URL:
Singh P, Goyal A, Tanwar A, Sharma S. Unusual presentation of calvarial tuberculosis masquerading as a cutaneous neoplasm: diagnosis by fine needle aspiration cytology. Ann Trop Med Public Health [serial online] 2013 [cited 2020 Jun 3 ];6:347-349
Available from: http://www.atmph.org/text.asp?2013/6/3/347/121005


Full Text

 Introduction



Tuberculosis is an endemic public health problem in developing countries. It poses a diagnostic problem especially when located in rare sites like cranial bones.Calvarial tuberculosis is usually considered a rare manifestation of tuberculous lesions elsewhere in the body but primary calvarial tuberculosis is even rarer. [1]

The aim of this case report is to highlight the role of Fine Needle Aspiration Cytology (FNAC) for diagnosis and obviating the need for invasive surgical procedure. The first report of diagnosis of calvarial tuberculosis by FNAC was published in 2000 by Mehrotra et al. [2] Subsequently there have been scanty reports available on the subject.

 Case Report



A 19 years old girl resident of Western Uttar Pradesh, India reported to our institute with a swelling on the scalp in the left frontal region for four months. There was no history of trauma. She was clinically diagnosed as a case of cutaneous neoplasm. On examination a scalp swelling of 2 × 2 cm in size, fluctuant with edematous and erythematous base and overlying discharging sinus was located in the region of left frontal bone [Figure 1]. The routine hematological parameters were normal except for raised ESR of 30 mm at one hour. X-ray of the skull showed a lytic bone lesion in left frontal bone with overlying soft tissue opacity. CT scan of the skull showed an irregular erosion and destruction of left sided frontal bone involving outer table and diploic space with an overlying soft tissue swelling [Figure 2]. The inner cortex though thinned out however was intact with no underlying extension.There was no evidence of organomegaly and lymphadenopathy. Chest X-ray was normal. Mantoux test was positive with induration 26 × 26 mm. Tests for HIV antibodies were negative and VDRL was non- reactive. The sputum sample was negative for Mycobacterium tuberculosis (MTB). Fine needle aspiration from the swelling yielded thick yellowish material. Microscopically, the smears showed granulomas comprising of epithelioid cells, giant cells and lymphocytes in the background of caseous necrotic material [Figure 3]. Direct smear was positive for acid fast bacillus (AFB) [Figure 3] Inset]. The culture of aspirated material was positive for MTB. Polymerase Chain Reaction (PCR) of aspirated material was also positive for tuberculosis.{Figure 1}{Figure 2}{Figure 3}

She was diagnosed as a case of primary tuberculosis of the frontal bone and was put on ATT as per WHO protocol. The sinus healed and swelling disappeared within 03 months of treatment and radiological recovery was noted after 6 months of anti-tuberculous therapy.

 Discussion



Calvarial tuberculosis is a rare disorder even in communities with high incidence of tuberculosis. Tuberculous involvement of calvarium is rare and even rarer is primary calvarial tuberculosis. Tuberculosis affecting bones accounts for 1% of tuberculosis infection, but only 0.2-1.3% of these are estimated to suffer from tuberculosis of the skull. [1] The first report was documented by Reid in 1842 from Germany. [3]

The patients of calvarial tuberculosis tend to be younger in age and it is rare in infancy. About half of the patients reported in literature were younger than 10 years and 75-90% of the patients were younger than 20 years. [4] The prevalence of the disease is equal in both the sexes.

Isolated calvarial tuberculosis is rare but can be seen in association with pulmonary tuberculosis, tubercular osteomyelitis involving other bones, cervical lymphadenitis, renal and intestinal tuberculosis. [5] Spread is also known to occur from tuberculous mastoiditis, orbit or spinal tuberculosis. The latent period of involvement of calvarium from the primary focus of pulmonary tuberculosis is estimated to be on average one year. [1]

The frontal and parietal bones having greater areas of diploic space and being cancellous are more vulnerable to involvement. Haematogenous spread from an extracalvarial focus leading to the lodging of the bacilli in the diploic spaces of the skull bones is the primary event in the pathogenesis. Further course depends on the immune status of the individual and virulence of the bacilli. Accordingly when host resistance is low or the virulence of the organism is high, there is proliferation of bacilli resulting in the obliteration of capillaries and replacement of bony trabeculae by granulation tissue. The concentrically placed proliferating fibroblasts encircle the tubercular granulation tissue preventing its extension through the bone. When destruction occurs, outer table is the first to be involved, though both the tables can be affected. [6]

Lymphatic spread from a primary focus explains the rarity of the calvarial tuberculosis, as the skull is deficient in lymphatic supply. [7] Trauma has also been incriminated to cause skeletal tuberculosis; the possible mechanisms include rich vascularity of the skull bone or low resistance and the trauma unmasking the latent infection. [8] It is postulated that the inflammation at the site of trauma may harbour or attract mycobacterium rich inflammatory cells, thus initiating the lesion. [7] In our case no history of trauma was documented but unnoticed trauma which has escaped the patient's attention might have been the possible cause of primary tuberculosis.Moreover, there was also no evidence of any primary active focus of tuberculosis elsewhere in the body in our patient. According to Chambers et al.,[9] the rare occurrence of cranial and calvarial tuberculosis is due to the peculiar blood supply of flat bones which makes it difficult for Mycobacterium tuberculosis to settle there.

The common mode of presentation is painless, soft and fluctuant scalp swelling. The cutaneous attachment and sinus formation are late features and may even resemble a cutaneous neoplasm.

Plain X-ray usually shows areas of rarefaction and sclerosis without any reactionary bone formation which is characteristic of skeletal tuberculosis. CT scan reveals areas of bone destruction, scalp swelling and varying degree of intracranial involvement. [7]

A definitive diagnosis can be made by identification of AFB from the smears or biopsy specimens. FNAC is a simple, non-invasive procedure which yields the cytological diagnosis of tuberculosis on the basis of necrotizing granulomas supplemented by AFB positivity detected on ZN stain. Awareness of this procedure obviates the need for an elaborate operative procedure for diagnosis. In the developed and developing countries, the importance of newer non- invasive techniques like FNAC for diagnosis cannot be over-emphasized. [2] Culture and PCR of the aspirated material further confirms the diagnosis.

The treatment of calvarial tuberculosis is predominantly ATT medication as per WHO protocol and surgery, if indicated. In all cases, the response is good with complete resolution of the lesion.

In conclusion, primary calvarial tuberculosis is an unusual and rare presentation of a common entity. FNAC is infallible tool for early diagnosis since tuberculosis is potentially curable disease.

References

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